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Libro resumenes lacame 2014

This document provides information about the XIV Latin American Conference on the Applications of the Mössbauer Effect (LACAME 2014), including: - A brief history and importance of the LACAME conferences for the Mössbauer spectroscopy community in Latin America. - Details about LACAME 2014 such as dates, location, organizers, and topics to be covered. - Lists of invited speakers, participating speakers, and poster presenters.

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EDITADO POR: Agustin Cabral Prieto (ININ) Eduardo Carpiette (Dirección de Educación Continua ya Distancia – UAEM) Lorena Nara (IPN) Tobías Noel Nava (IMP) Oscar Olea (Facultad de Química-UAEM) IMPRESO Metepec, Estado de México. Octubre 2014 DISEÑO: Dirección de Educación Continua ya Distancia – UAEM
Índice de trabajos LACAME 2014 ..................................................................................................................................................... 1 Topics .................................................................................................................................................................. 2 Latin American Conference on the Application of Mössbauer Spectroscopy .................................................... 3 25 AÑOS DE CONGRESOS LATINOAMERICANOS DE ESPECTROSCOPÍA MÖSSBAUER................................. 5 Committees ........................................................................................................................................................ 7 Sponsors ............................................................................................................................................................. 8 Thanks ................................................................................................................................................................ 9 SCIENTIFIC PROGRAM ...................................................................................................................................... 10 Invited Speakers ............................................................................................................................................... 11 T02: CONTRIBUTIONS OF MÖSSBAUER SPECTROMETRY TO THE STUDY OF SOME OXIDE DILUTED MAGNETIC SEMICONDUCTORS: A CRITICAL REVIEW .......................................................................... 12 T05: CHEMISTRY AND ENVIRONMENTAL APPLICATIONS OF HIGH‐VALENT IRON‐OXO SPECIES ................ 13 T05: DESIGN OF SELF AND MATRIX‐SUPPORTED SYSTEMS OF IRON OXIDE NANOPARTICLES FOR CATALYTIC APPLICATIONS ................................................................................................................... 14 Participations .................................................................................................................................................... 15 T02: MÖSSBAUER SPECTROSCOPY AS SOURCE OF COMPLEMENTARY A PRIORI INFORMATION TO SOLVE CRYSTAL STRUCTURES FROM XRD POWDER DATA ............................................................................. 18 T02: NUMERICAL ANALYSIS OF BROAD MÖSSBAUER SPECTRA BY USING SIMPLE DISTRIBUTION FUNCTIONS .......................................................................................................................................... 19 T02: STRUCTURAL AND HYPERFINE PROPERTIES OF M‐DOPED SNO2 (M=TRANSITION METAL OR RARE EARTH ELEMENT) NANOPARTICLES ..................................................................................................... 20 T04: SYNTHESIS AND CHARACTERIZATION OF MAGNETITE NANOPARTICLES FUNCTIONALIZED WITH CARBOXYL AND AMINO ACIDS FOR BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS ................. 23 T05: PHOTOCATALYTIC EFFECT AND MÖSSBAUER STUDY OF IRON TITANIUM SILICATE GLASS PREPARED BY SOL‐GEL METHOD ........................................................................................................................... 25 T06: 57Fe‐MÖSSBAUER STUDY OF ZIRCONIA CONTAINING IRON VANADATE CLYSTALLIZED GLASS WITH HIGH ELECTRICAL CONDUCTIVITY ....................................................................................................... 27 T08: CORRELATION BETWEEN MILLING TIME OF POWDER, AND THE TEMPERATURE OF SUBSTRATE ON THE PROPERTIES OF NdFe THIN FILMS ................................................................................................ 30 T08: IN γ‐Fe2MnGa COMPOUND DO Fe AND Mn ORDER MAGNETICALLY AT THE SAME TEMPERATURE? DO THEY COUPLE PARALLEL OR ANTIPARALLEL AT LOW TEMPERATURES? ....................................... 31
T08: MAGNETIC PROPERTIES OF TWO CORE/SHELL NANOPARTICLES COUPLED VIA DIPOLAR INTERACTION ............................................................................................................................................................. 32 T08: MÖSSBAUER AND STRUCTURAL STUDY OF ALLOYS Fe1‐XVX OBTAINED BY MECHANICAL ALLOYING .. 33 T08: MÖSSBAUER INVESTIGATIONS ON THE DESORBTION OF HYDROGEN AND HYDROXYL FROM THE IRON OXIDE NANOPARTICLES .............................................................................................................. 34 T08: MÖSSBAUER STUDY OF ALLOYS Fe67.5Ni32.5, PREPARED BY ALLOY MECHANICAL ................................ 35 T08: SPIN DYNAMICS IN COEXISTING ANTIFERROMAGNETIC AND SPINGLASS STATES OF MULTIFERROIC LEAD PEROVSKITES .............................................................................................................................. 36 T08: STUDY OF STRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF Fe DOPED, Co DOPED, AND Fe‐Co CO‐DOPED ZnO .................................................................................................................................... 37 T08: SYNTHESIS AND CHARACTERIZATION OF NixCo1‐xFe2O4 Nanoparticles ................................................ 38 T08: SYNTHESIS OF SILVER ‐COATED MAGNETITE NANOCOMPOSITE FUNCTIONALIZED BY AZADIRACTHA INDICA .................................................................................................................................................. 39 T10: MÖSSBAUER AND XRD CHARACTERIZATION OF THE PHASE TRANSFORMATIONS IN A Fe‐Mn‐Al‐C AS. CAST ALLOY DURING TRIBOLOGY TEST ................................................................................................ 42 T10: STRUCTURAL STUDY ON Li2Fe1‐xNixSiO4 ............................................................................................... 43 Posters .............................................................................................................................................................. 44 Authors index ................................................................................................................................................. 133
1 LACAME 2014 XIVth Latin American Conference on the Applications of the Mössbauer Effect ‐ LACAME 2014 LACAMEs are special scientific events. They are regional meetings that aim at stimulating the development of Mössbauer Spectroscopy (MS) in Latin American countries, all of them with unparallel common cultural roots, but most of them with limited resources. MS is a particular technique suitable for promoting the scientific development in these societies. The organization of a conference like LACAME gives the young scientists of the region who do not have many chances to visit other laboratories or attend the ICAME meetings the opportunity to improve their scientific progress, and brings to the scientific communities and young researchers the feeling of how experimental physics can be performed at a high level. As a consequence of these meetings, the Mössbauer community is growing in Latin America. New laboratories have been set up and the improvement of the existing ones has been observed. The collaboration, interchange and scientific agreements between laboratories, some of them isolated prior to the LACAME conferences, have been greatly enhanced. The XIVth Latin American Conference on the Applications of the Mössbauer Effect ‐ LACAME 2014 will be held from November 10th to 14th, 2014 in Mexico. LACAME started in 1988 in Rio de Janeiro and has grown steadily since then, changing the venue every two years from different nations where Mössbauer research laboratories exist. We do believe that the special ingredient added by LACAME will help flourish the development of science and MS in this part of the world; let us hope this trend continues growing. We welcome you all to LACAME‐2014. November 2014.
2 Topics T01‐ Advances in experimentation and Data Processing T02‐ Amorphous, Nanocrystals and Nanoparticles T03‐ Applications in Soils, Mineralogy, Geology, Cements and Archaeology T04‐ Biological and Medical Applications T05‐ Catalysis, Corrosion and Environment T06‐ Chemical Applications, Structure and Bonding T07‐ Industrial Applications T08‐ Magnetism and Magnetic Materials T09‐ Multilayers, Thin Films and Artificially Structured Materials T10‐ Physical Metallurgy and Materials Science
Latin American Conference on the Application of Mössbauer Spectroscopy 3 Elisa Baggio Saitovitch We can not speak about Mössbauer spectroscopy in Latin America without speaking about Jacques Danon who passed away in 1989. He has initiate to work already in 1960 in this field at Brazilian Center for Research in Physics (CBPF), in Rio de Janeiro. He always insisted that we should not compete with the countries of north hemisphere but exercise our creativity in scientific research, looking for topics related with our region or having a new approach in frontier topics, addressing topics that can be studied in the frame of the scientific and technologic difficulties (not facilities). He always said: Lo que es importante, no son las técnicas y computadores, son las ideas. Solamente la creatividad puede generar un verdadero progreso tanto en la ciencia como en cualquier campo de la actividad humana. In the early days of Mössbauer spectroscopy in Latin America there was more interaction; this was not the case when I started to work in Mössbauer spectroscopy. Danon always mentioned collaboration with Augusto Moreno y Moreno, in Mexico, Carlos Abeledo and Albert Fech. He published the first lectures in Spanish on the Mössbauer effect given at the Escuela Latino Americana de Física that was held in Mexico, in 1968. In 1985, while participating in a commission to discuss the future of CLAF (Latin American Center for Physics) I realized how bad the scientific collaboration among Latin American groups doing research was; they tend to give priority to the interaction with groups in north hemisphere. The collaboration with our neighbors in Latin America would not occur spontaneously, it was necessary to be worked out because, more than the proximity, they have common problems. With these ideas in mind I went to a Brazilian meeting in Mössbauer spectroscopy, which was the last from a series going through all the groups (see H. Rechenberg report). Our idea was to change a bit the scope including all Brazilian groups working in Hyperfine Interaction. There I have made another proposition: open the meeting to all the Mössbauer groups in Latin America. This proposition was accepted and I suggested that the Chairperson should be Jacques Danon, knowing that I should do the heavy work. In November 1988 we organized in Rio, with the help of Rosa Scorzelli the first LACAME; the name of our meeting was inspired in the ICAME. At those days we were able to bring together more than 129 participants! I believe that most of the people working in this area came to Rio. It was difficult to contact all the people, in this case the contribution of Danon
was essential: he knew everybody. But there was no e‐mail, no telephone and the best communication was by telegram and fax. For the first time I learned about Raiza from Havana, Jaen in Panama or Aburto in Mexico. The situation in Brazil in 1989 was very favorable for our purpose; the inistry of Science and Technology had been just created. I was able to get support from several Brazilian institutions and foundations as CBPF, CNPq, CNEN, FINEP, CAPES and CLAF. The total budget was about US$ 50 000 and the invitation included air ticket, hotel and meals. Circa of 10 non Latin American scientist specialists in different fields were invited and contributed to the success of the conference. I still remember how the eyes of some students were shining when they could listen to these known specialists in Mössbauer spectroscopy. All the effort was worthwhile! After that we had the nice meeting in Cuba with the conversation with Fidel Castro and many non Latin American participants. Argentina, Chile, Peru, Colombia, Venezuela, Panama and Mexico (in 2004), it has been a long way, with a lot of efforts (the chair persons know it well), but the result is excellent. The number of participants has decreased along these 15 years. May be there is now less people in the field or less funds available, this we still need to find out. In Brazil the strong group of Porto Alegre, where I was introduced to Mössbauer spectroscopy, has only a minor activity and sometimes does not participate even in the Brazilian meetings. To compensate now we have the group of Vitoria and Ouro Preto, which are very active and have organized the last Brazilian meetings. New groups have been created in Peru (Victor Peña Rodrigues) and Colombia (Perez Alcazar) and they are very active as we could see in the last conferences. From the successive meetings we can follow the development of some students like Restrepo from Colombia. He gave a talk in Caracas as a senior scientist! Despite this conference became smaller they are very dynamic with a lot of discussion and interesting questions. I hope we can keep this atmosphere for Mexico. This meeting have been very important for the participants, researchers and students that do not have the opportunity to participate in the ICAMEs. Traditionally some few non Latin American specialists are invited speakers together with local researchers from areas where Mössbauer spectroscopy can be applied. For example, in Venezuela we had some talk about Petroleum industry. We try to avoid inviting the same non Latina American specialists in two successive meetings in order to cover different areas. The LACAME has contributed for the collaboration among LA groups and for spreading this spectroscopy in LA. All the applications are being studied, including minerals, meteorites, soils, superconducting and magnetic materials, milling, catalyses, corrosion, chemistry, thin films, heavy fermions, 4
etc. However we still hope to be able to improve the shearing of the facilities among the groups and establish bilateral official exchange programs. On a regular basis the LACAME conferences are organized in Latin America, each two years and we succeeded in organizing and reinforcing the collaboration among the Mössbauer community in Latin America. Except for the conference in Chile the Proceedings have been published by Hyperfine Interaction. 25 AÑOS DE CONGRESOS LATINOAMERICANOS DE ESPECTROSCOPÍA MÖSSBAUER Por estos días se están cumpliendo los 25 años de nuestra existencia como comunidad latinoamericana de espectroscopía Mössbauer. Es con enorme alegría que queremos celebrar este aniversario. En 1988, con la excepción de Brasil, que realizaba desde1982 encuentros locales de jóvenes investigadores, en nuestro continente había algunos laboratorios dispersos con investigadores que pretendíamos hacer buena ciencia sin muchos medios a pesar las grandes dificultades que se presentaban en nuestros países. Esto cambiaría para siempre cuando, entre el 31 de octubre y el 4 de noviembre de 1988 se organizó el primer Congreso Latinoamericano de Espectroscopía Mössbauer. Allí nos conocimos y rápidamente nos identificamos como formando parte de una comunidad científica. En estos veinticinco años, hemos crecido individual y colectivamente y nos sentimos miembros de una realidad que trasciende las fronteras de nuestros países para constituirse en una unidad latinoamericana que encuentra gran placer y ventaja en colaborar con colegas de otros países de la región y reencontrarse con viejos (y no tan viejos) amigos cada dos años en los LACAME y en numerosas colaboraciones entre distintos miembros de la comunidad. En este tiempo hemos visto aparecer laboratorios de luz sincrotrón, centros de microscopía electrónica, la Internet. En nuestras propias instituciones se han agregado nuevas técnicas que como la calorimetría o la magnetometría nos han permitido profundizar enormemente nuestras investigaciones. Sin embargo, todo esto no ha desviado nuestra convicción de que lo que nos une es la espectroscopía Mössbauer. En otros continentes esta realidad es de mucha menor intensidad o simplemente no existe ya. Pero ciertamente en América latina nuestros congresos gozan de prestigio y de entusiasmo, con nuevos jóvenes que se sienten parte de esta comunidad convocante que tiene un gran reconocimiento internacional. 5
Por eso, el Comité Latinoamericano de Espectroscopía Mössbauer saluda jubilosamente a los colegas latinoamericanos y hace votos para que las nuevas generaciones tengan éxito en sus esfuerzos de continuar y mejorar lo que ya ha sido hecho hasta aquí. 6
7 Committees Intenational Committee E.M. Baggio Saitovitch CBPF Brazil N.R. Furet Bridón CNIC Cuba F. González Jiménez UCV Venezuela J.A. Jaén UP Panamá R.C. Mercader UNLP Argentina N. Nava IMP México V.A. Peña Rodríguez UNMSM Perú G.A. Pérez Alcázar UV Colombia Carmen Pizarro USACH Chile Local organizing committee Humberto Arriola S. Facultad de Química, Universidad Nacional Autónoma de México Agustín Cabral Prieto Instituto Nacional de Investigaciones Nucleares Naria Adriana Flores Fuentes Escuela Superior Físico‐Matemáticas, Instituto Politécnico Nacional Arturo García Borquez Escuela Superior Físico‐Matemáticas, Instituto Politécnico Nacional Eduardo Gómez Garduño DECyD, Universidad Autónoma Estado México Ezequiel Jaimes Figueroa DECyD, Universidad Autónoma Estado México Rafael López Castañares Facultad de Química, Universidad Autónoma Estado México Fabiola Monroy Guzmán Instituto Nacional de Investigaciones Nucleares Noel Nava E. Instituto Mexicano del Petróleo Oscar Olea Cardoso Facultad de Química, Universidad Autónoma Estado México Oscar F. Olea Mejia Facultad de Química, Universidad Autónoma Estado México Jesús Soberón M. Investigador
8 Sponsors Abdus Salam International Centre for Theoretical Physics Sociedad Química de México Universidad Autónoma del Estado de México Consejo Mexiquense de Ciencia y Tecnología Instituto Nacional de Investigaciones Nucleares Instituto Mexicano del Petróleo
9 Thanks Los Comités Internacional y Local de la XIV Latin American Conference on the Applications of the Mössbauer Effect aprecian y agradecen profundamente al Rector de la Universidad Autónoma del Estado de México, Dr. en D. Jorge Olvera García, por habernos permitido realizar esta conferencia en las instalaciones de la Dirección de Educación Continua y a Distancia (DECyD‐UAEM). Así mismo, agradecemos al Maestro Ezequiel Jaimes Figueroa, Director de la DECyD‐UAEM, por todo el apoyo y facilidades que nos brindó durante la organización de dicha conferencia, así como a su equipo de trabajo por su invaluable aportación para preparar el compendio de los resúmenes que se presentan en este libro.
10 SCIENTIFIC PROGRAM SUNDAY NOV. 9 MONDAY NOV. 10 TUESDAY NOV. 11 WEDNESDAY NOV. 12 THURSDAY NOV. 13 FRIDAY NOV. 14 9:00 Opening Ceremony 9:00 J A Jaen 9:00 Mira Ristic VideoC 9:00 Elisa Baggio‐ Saitovitch 9:00 Roberto C. Mercader 9:30 Cesar A Barrero M 9:45 Coffee 9:45 Coffee 9:45 Coffee 10:15 Coffee 10:05 V Sharma 10:00 Coffee 10:05 F.J. Litterst 10:05 Edilso Reguera 10:35 Edson P 10:50 W. T. Herrera City tour 10:50 P.M.A. Caetano 11:10 Dagoberto Oyola Lozano 11:30 Herojit Singh 11:50 J.J. Beltrán 12:10 J. L. López 10:50 Concluding Remarks 11:20 G.A. Pérez Alcázar 11:30 S. Kubuki 11:40 José Domingos Fabris 11:50 Aguirre‐Contreras Next LACAME 12:00 Y. Takahashi, 12:10 Benítez Rodríguez 12:20 Lunch 12:30 Lunch 12:30 Lunch 14:00 Rojas Martínez 14:00 POSTER SESSION1 14:00 POSTER SESSION2 14:20 J. A. H. Coaquira 18:00 Registration Latin American Round Table 19:00 – 21:00 Welcome
Invited Speakers 11
T02: CONTRIBUTIONS OF MÖSSBAUER SPECTROMETRY TO THE STUDY OF SOME OXIDE DILUTED MAGNETIC SEMICONDUCTORS: A CRITICAL REVIEW J.J. Beltrán1, A. Punnoose2, K. Nomura3, E.M. Baggio-Saitovitch4, and C.A. Barrero1 1Grupo de Estado Sólido, Facultad de Ciencias, Universidad de Antioquia, Medellín, Colombia. 2Department of Physics, Boise State University, Boise, USA 3Department of Applied Chemistry, School of Engineering, The Tokyo University, Tokyo, Japan 4Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brazil. 12 *Corresponding author: e-mail: cesar.barrero@udea.edu.co Keywords: Fe doped ZnO, Fe doped SnO2, nanoparticles. Topic: T02- Amorphous, Nanocrystals and Nanoparticles In 2005, the prestigious journal Science [1] posed a list of 125 unsolved scientific questions, one of them being: “is it possible to create magnetic semiconductors that work at room temperature?”. In 2008, Coey et al. [2] mentioned that the origin of the magnetism in Diluted Magnetic Semiconductors (DMS) is one of the most puzzling investigations. And to date we can say that the understanding of such phenomena is still a great challenge in materials science. In fact, there is no agreement between the various theoretical and experimental studies performed on the origin of the ferromagnetic signal in DMS, particularly in Oxide-DMS (ODMS). From the experimental side, the use of different characterization techniques, including Mössbauer spectrometry (MS), is an important requirement to achieve a better understanding of the phenomena. In this presentation we will show some examples of the contributions that 119Sn and 57Fe MS have done to the characterization of Fe-doped ZnO [3], Fe-Co codoped ZnO [4], Fe-doped SnO2 [5-7] and Fe-Sb codoped SnO2 [8,9] nanoparticles. We will show how this technique has contributed to the: (i) demonstration of the absence of both spurious phases and clustering of dopants, (ii) determination of the preferable sites, high or low spin character, and oxidation states of the transition metal (TM) ions, (iii) identification of the preferable location of the TM ions, either at the surface, at the interior or in the whole nanoparticles, (iv) identification and characterization of defects, (v) proper characterization of the electronic, crystallographic, and magnetic properties, and their possible relations, (vi) and determination of the TM ions that are involved in the magnetic ordering. References [1] Kennedy and Norman, Science 309 (2005) 82. [2] J.M.D. Coey, K. Wongsaprom, J. Alaria, and M. Venkatesan, J. Phys. D.: Appl. Phys. 41 (2008) 134012. [3] J.J. Beltrán, J.A. Osorio, C.A. Barrero, C.B. Hanna and A. Punnoose, J. Appl. Phys. 113 (2013) 17C308. [4] J.J. Beltrán, C.A. Barrero, A. Punnoose, J. Phys. Chem. C, V. 19 (3) (2014) [5] A. Punnoose, K. Dodge, J.J. Beltrán, K.M. Reddy, N. Franco, J. Chess, J. Eixenberger, and C.A. Barrero, J. Appl. Phys. 115 (2014) 17B534 [6] J.J. Beltrán, L.C. Sánchez, J. Osorio, L. Tirado, E.M. Baggio-Saitovitch, and C.A. Barrero, J. Mater. Sci. 45 (2010) 5002 [7] K. Nomura, C.A. Barrero, J. Sakuma, and M. Takeda, Phys. Rev. B 75 (2007) 184411 [8] K. Nomura, C.A. Barrero, K. Kuwano, Y. Yamada, T. Saito, E. Kuzmann, Hyperfine Interact. 191 (2009) 25. [9] K. Nomura, E. Kuzmann, C.A. Barrero, S. Stichleutner, and Z. Homonnay, Hyperfine Interact. 184 (2008) 57.
T05: CHEMISTRY AND ENVIRONMENTAL APPLICATIONS OF HIGH-VALENT IRON-OXO SPECIES Virender K. Sharma1*, Radek Zboril2, Libor Machala2, and Karolina Siskova2 1Departent of Environmental and Occupational Health, School of Public Helath, Texas A&M University 1266 TAMU, SPH 101, College Station, Texas. 2 Regional Centre of Advanced Technologies and Materials, Departments of Experimental Physics and Physical Chemistry, Faculty of Science, Palacky University, 78371 Olomouc, Czech Republic 13 *Corresponding author: e-mail: vsharma@sph.tamhsc.edu Keywords: Ferrate, oxidation, decontamination Topic: T05- Catalysis, Corrosion and Environment The chemistry of iron has been developed early in the history of mankind as it is the basic metal of the industrial society and its ore is profoundly present globally. Iron as the most abundant transition element, present in alloy with nickel, and constitutes about a third of entire mass of the Earth’ crust. Iron is important for most of the living organisms. Iron has a unique range of valence states from zero to +6 oxidation states, which have numerous applications in medicine, energy, nanotechnology, biocatalysis, energy, and environmental remediation. Examples of biocatalysis include involvement of high-valent oxoiron(IV) (FeIV = O) and oxoiron(V) (FeV = O) species in a number of enzymatic systems (1). These high-valent iron species participate in halogenation, epoxidation, and hydroxylation reactions. In the last decade, our research group is researching the simple oxo-compounds of higher-valent iron species, commonly called ferrates (FeVIO42-, Fe(VI), FeVO43-, Fe(V), and FeIVO44-, Fe(IV)) in aqueous solution, which have shown their applications in energy materials, green organic synthesis, and waste remediation (2). Examples of remediation are oxidative transformations of toxic inorganic and organic contamination to non-toxic by products, inactivation of virus and bacteria, and removal of toxic metals (e.g. arsenic) (3, 4). The focus of the presentation will be on demonstrating the chemistry and applications of these high-valent iron species in water treatment technology. Mössbauer spectra of Fe(VI), Fe(V), Fe(IV) and Fe(III) species can be used to distinguish these iron species in the solid phase and in the solution mixture. The isomer shift values of ferrates decreased almost linearly and can be expressed as Δ (mm s-1) = 1.084 – 0.326 × OS (1) Mechanisms of the reactions of ferrates with different contaminants were studied using Mössbauer spectroscopy in conjunction with other spectroscopic and surface techniques. Figure 1 shows the example of studying the removal of arsenic by Fe(VI) in which ex-situ and in-situ removal by Fe(III), generated from Fe(VI), differ. Figure 1. Different mechanisms of arsenic removal by Fe(III), ex-situ sorption (left) and Fe(VI) induced in-situ structural incorporation (right) (5). References [1] J. Hohenberger, K. Ray, and K. Meyer, Nature Commun. 3720 (2012). [2] V. K. Sharma, Coord. Chem. Rev. 257 (2013) 494-510. [3] E. Casbeer, V.K. Sharma, Z. Zajickova, and D.D. Dionysiou, Environ. Sci. Technol., 47 (2013), 4572-4580. [4] V.K. Sharma, J. Environ. Manage. 92 (2011), 1051-1073. [5] R. Prucek, J. Tucek, J. Kolařík, J. Filip, Z. Marušák, V.K. Sharma, and R. Zboril, Environ. Sci. Technol. 47 (2013) 3283-3292.
T05: DESIGN OF SELF AND MATRIX-SUPPORTED SYSTEMS OF IRON OXIDE NANOPARTICLES FOR CATALYTIC APPLICATIONS I.O. Pérez de Berti1, J.F. Bengoa1, S.G. Marchetti1, R.C. Mercader2* 1CINDECA, CONICET, CICPBA, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 Nº 257, 1900 La Plata, Argentina 2 Instituto de Física La Plata, CCT-CONICET, Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 115 y 49, 1900 La Plata, Argentina *Corresponding author: e-mail: mercader@fisica.unlp.edu.ar Keywords: Fischer-Tropsch reaction, semi-model catalysts, Mössbauer characterization, pre-synthesized nanoparticles Topic: T05- Catalysis, Corrosion and Environment 14 Metallic nanoparticles are widely used as supported catalysts in many industrial chemical reactions. A detailed understanding of the enhancement that the nanoparticles bring about in the stability, activity, and selectivity of the solids requires quasi-model catalysts with well-defined surfaces and supported nanoparticles of homogeneous size. The usual way of synthesizing catalysts of supported nanoparticles is to impregnate the solid with a solution that contains the metal salts that will give rise to the catalyst. However, this route doesn't necessarily lead to a catalyst close to the ideal conditions. The Fischer-Tropsch synthesis is a reaction in which a mixture of hydrogen and carbon monoxide converts into liquid hydrocarbons mediated by the presence of a catalyst. The reaction process can be written as: nCO + (2n+1) H2  CnH2n+2 + nH2O In spite that it was developed in the 1920s and that it has been intensively used over many decades, the intrinsic mechanism of how it proceeds is not fully known. In particular, the activity and selectivity depend on factors that are not easy to isolate. One of them is the so-called structure sensitivity. To be able to study the diverse influence of the different parameters in the activity and selectivity of the catalysts, we set about to prepare quasi-model catalysts by a route different from the usual one; we pre-synthesized systems of narrowly size-distributed nanoparticles and introduced them afterwards into the already synthesized matrix. In this talk we will describe the results obtained after the preparation of Fischer-Tropsch catalysts made up 3 nm maghemite nanoparticles supported on SBA-15 matrices. The catalysts were prepared by pre-synthesizing γ-Fe2O3 particles and further embedding them into a modified SBA-15 matrix. The results showed that the solid kept its structural properties over impregnation, activation and catalytic reaction performed in realistic conditions. Out of the many techniques by which we characterized the solids, Mössbauer spectroscopy was the one that yielded the more helpful results allowing the identification of all the relevant intervening iron species. Figure 1. Mössbauer spectra of γ-Fe2O3/SBA-15 catalysts measured at the temperatures indicated after a catalyst reaction conducted at 20 atm. As an example of the results that will be considered in the talk, Fig. 1 displays the Mössbauer spectra of two catalysts that produced a high activity and a good olefin/paraffin ratio over the Fischer-Tropsch reaction at 20 atm after being activated in a CO-H2: CO atmosphere (left) and H2 atmosphere (right). Both solids underwent catalysis tests and were measured in a specially designed cell that enabled keeping the same reactor atmosphere when taken over to the Mössbauer spectrometer.
Participations 15
T01‐ Advances in experimentation and Data Processing 16
T02‐ Amorphous, Nanocrystals and Nanoparticles 17
T02: MÖSSBAUER SPECTROSCOPY AS SOURCE OF COMPLEMENTARY A PRIORI INFORMATION TO SOLVE CRYSTAL STRUCTURES FROM XRD POWDER DATA Edilso Reguera Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute, Mexico, D. F., Mexico; Corresponding author: e-mail: edilso.reguera@gmail.com Topic: T02- Amorphous, Nanocrystals and Nanoparticles Mössbauer spectra provide information on the coordination geometry for the atom involved in the - resonant nuclear absorption, on the nature of first and second neighbors, and on its electronic structure and relative occupation of structural sites in the solid. All this information is relevant to solve the crystal structure of new materials from XRD powder data. To solve the crystal structure of a new material the best option is to have diffraction data from a single crystal. Such possibility is available only for a small fraction, usually < 10 %, of practical situations. In a single crystal experiment, the diffraction pattern is the Fourier Transform for the sample in the inverse space and the crystal model to be refined (in the direct space) is obtained from the Inverse Fourier Transform of the recorded diffraction pattern. In XRD powder experiment, the 3D structural information is projected in 1D space. From this fact, the crystal structure for this kind of data must be solved through an ill-posed problem. This supposes the availability of a priori structural information or boundary conditions for the mathematical problem to be solved. Such a priori information is usually obtained from spectroscopic techniques. Nuclear, electronic and vibrational spectra contain information on the local symmetry (coordination geometry) and nature of the first neighbors for the atom(s) involved resonant absorption and re-emission. In this contribution, the scope of Mössbauer spectroscopy in that sense is discussed, from several illustrative examples, where the crystal structure was solved and then refined, using the corresponding Mössbauer spectra as source of the required a priori structural information. 18
T02: NUMERICAL ANALYSIS OF BROAD MÖSSBAUER SPECTRA BY USING SIMPLE DISTRIBUTION FUNCTIONS B. Aguilar-García1, A. Sandoval-Nandho1, I. García-Sosa2 O. R. López-Castañares3, O. Olea-Cardoso3 and A. Cabral-Prieto2(*) 1Universidad Autónoma Metropolitana-Cuajimalpa, Avenida Vasco de Quiroga 4871, Cuajimalpa, Santa Fe Cuajimalpa, 05300 Ciudad De México, D.F. 2 Instituto Nacional de Investigaciones Nucleares, Departamento de Química, Apdo. Postal 18-1027, Col. Escandón, Deleg. M. Hidalgo, C. P. 11801, México. D. F., México. 3Universidad Autónoma del Estado de México, Paseo Universidad #100, Universitaria, 50130 Toluca de Lerdo, Estado de México *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: Broad Mössbauer spectra, hyperfine distributions, goettite Topic: T02- Amorphous, nanocrystal and nanoparticles 19 The analysis of broad Mössbauer spectra is usually handled by using the convolution between the Gaussian and Lorentzian lines. There are, however, many cases were this convolution does not give meaningful results because the Mössbauer spectra are the result of a complex superposition of several patterns and the discrete hyperfine parameters are difficult to calculate from them. In such cases the use of hyperfine distribution functions are preferred [1]. In this paper simple distribution functions are used to analyze the Mössbauer spectrum of Goethite nanoparticles. The asymmetrical triangle is shown in Fig. 1. Figure 1 (a) Mössbauer spectrum of goethite nanoparticles recorded at 77K. (b) Asymmetrical triangular distribution function may be used to properly fit this spectrum. Typical representations of the hyperfine field distributions (HFD) for this nano material are as shown in Fig. 2 (a) and (b), obtained with known methods [1, 2]. Figure 2. (a) Step distribution function [1], (b) Fourier series expansion [2]. Figure 3. (a) Gaussian, (b, c) Rational, (d) binomial distribution functions. Figure 3 shows, on the other hand, three atypical representations of the HFD. The decaying curve, after the maxima, does not appear which seems to be unnecessary for cases like this. If it does such a decay is abrupt as indicated in figs. 1 (a). Fig. 2 (a) and (b) or Fig. 3 (b). In all these cases there is always a question left: what of the seven HFDs, here presented, represents best the experimental data. Morup et al. [3] reproduces the asymmetry of a Mössbauer spectrum by using an asymmetrical distribution function for the crystal size of nanomaterials. Thus, Fig. 3 (d) may be the best searched solution instead of Fig. 2 (b). In all presented cases the same order of magnitude for squared Ji is, however, acceptable. References [1] J. Hesse, A. Rübartsch, Journal of Physics E 7 (1974) 526. [2] Window, B.: J. Phys. E: Sci. Intrum. 4, 401 (1971) [3] S. MØrup , H. TopsØe and J. Lipka, Journal de Physique Colloque C6, sup.12, Tome 37, (1976) C6- 287.
T02: STRUCTURAL AND HYPERFINE PROPERTIES OF M-DOPED SNO2 (M=TRANSITION METAL OR RARE EARTH ELEMENT) NANOPARTICLES J. A. H. Coaquira1, F. H. Aragón1, J. C. R. Aquino1, R.Cohen2, L.C.C.M. Nagamine2, P. Hidalgo3, D. Gouvêa4 1Instituto de Física, Universidade de Brasília, Núcleo de Física Aplicada, Brasília DF 70910-900, Brazil. 2 Instituto de Física, Universidade de São Paulo, SP 05508-090,Brazil 3Faculdade Gama-FGA, Sector Central Gama, Universidade de Brasília, Brasília, DF 72405-610, Brazil. 4Departamento de Metalurgia e Engenharia de Materiais, Escola Politécnica, Universidade de São Paulo, São Paulo SP 05508-900, Brazil. *Corresponding author: e-mail: coaquira.ja@gmail.com Keywords: M-doped SnO2 nanoparticles, Mössbauer spectroscopy, structural properties Topic: T02- Amorphous, Nanocrystals and Nanoparticles The possibility of using the magnetic properties of magnetic gas sensing materials instead of their conventional electrical properties is moving forward the interest for dilute magnetic semiconductor oxides. The SnO2 compound is a wide band-gap (~3.5 eV) semiconductor and widely used as a conventional gas sensor due to its high reactivity with environmental gases. The doping of this semiconductor using transition metals changes its sensitivity, selectivity and time response with respect to a number of pollutant gases. However, the use of magnetic gas sensors requires that the sensing material shows magnetic order above room temperature. Although reports indicate room temperature ferromagnetic properties of transition-metal- doped SnO2 thin films and powders, the origin of that order is not clear yet [1]. 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 10.0 mol% 5% 2.5 mol% Transmission (a. u.) 7.5 mol% P (QS) P (QS) QS (mm/s) P (QS) QS (mm/s) P (QS) QS (mm/s) 0.0 mol% -8 -6 -4 -2 0 2 4 6 8 Velocity (mm/s) 0 1 2 3 4 5 6 7 QS (mm/s) 12 Experimental data 8 4 0 -4 Figure 1. Room-temperature Mossbauer spectra of Gd-doped SnO2 nanoparticles. Isomer shift (IS) as a function of the Gd content. In this work, we report the study of the structural and magnetic properties of M-doped SnO2 (M=transition metal or rare earth element) nanoparticles synthesized by a polymer precursor method [2]. X-ray diffraction patterns indicate the formation of only the rutile phase for the whole set of samples. Undoped SnO2 nanoparticles show an average particles size of ~11 nm and this size shows a decreasing tendency as the M content is increased, regardless the M dopant. This crystalline size is further corroborated by TEM images. Magnetic measurements, carried out in a wide range of temperature and applied magnetic field, suggest the coexistence of ferromagnetic and paramagnetic phases. Depending on the dopant content, a ferromagnetic behavior which survives until high temperatures is determined. Mössbauer spectra, carried out using a Ca119mSnO3 radiation source, show no evidences of magnetic splitting and, depending on the doping element (M), room temperature Mössbauer spectra are well resolved by considering doublets. The origin of these doublets and the effects on the quadrupole splitting and isomer shift due to the doping are discussed in this work. References [1] W. Wang, Z. Wang, Y. Hong, J. Tang, and M. Yu, J. Appl. Phys. 99 (2006) 0M115. [2] D. Gouvêa, A. Smith, J. P. Bonnet, Eur. J. Solid State Inorg. Chem. 33 (1996) 1015. 0 2 4 6 8 10 -8 IS (x10-3mm/s) Gd content (%)
T03‐ Applications in Soils, Mineralogy, Geology, Cements and Archaeology 21
T04‐ Biological and Medical Applications 22
T04: SYNTHESIS AND CHARACTERIZATION OF MAGNETITE NANOPARTICLES FUNCTIONALIZED WITH CARBOXYL AND AMINO ACIDS FOR BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS W. T. Herrera1, A.G. Bustamante Domínguez1, M. Giffoni2, E. Baggio-Saitovitch2 and J. Litterst3 1 Ceramics and Nanomaterials Laboratory, Department of Physics, National University of San Marcos (UNMSM), A.P. 14-0149, Lima 14, Perú. 2 Brazilian Center for Physics Research (CBPF), 22290-180, Rio de Janeiro, Brazil. 3 Institute for Physics of Condensed Matter, Technische Universität Braunschweig (TU Braunschweig), Mendelssohnstrasse 3, D-38106 Braunschweig, Germany. *Corresponding author: e-mail: wiliam@agdes.pe Keywords: magnetite nanoparticles functionalized, magnetic nanoparticles Topic: T04 - Biological and Medical Applications 23 This work involves the synthesis of magnetite nanoparticles (NPs) functionalized with lauric acid (LA), oleic acid (OA) and lysine (Lys). The synthesis was carried out using a chemical route of co-precipitation. This route allows the production of NPs functionalized using a basic infrastructure, low cost of production, the latter very important, especially if we consider the potential applications in the field of environmental remediation. In the case of biomedical applications also chemical route is the best alternative in this case however requires a more extensive characterization and clinical trials. After synthesis of functionalized NPs these were characterized with the techniques: X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). Of the analysis made by the different techniques we concluded that functionalized NPs are of very good quality. All were magnetic with magnetic saturation of 60 emu/g, for the case of NPs coated with AL. The XRD and TEM measurements show that the NPs have an average size between 9 and 11 nm with spinel crystal structure with lattice parameter of 8.37 Å. XPS measures determined that iron atoms has a valence of +3 and +2, with a total ratio of iron atoms Fe3+:Fe2+ of 2:1. Of the FTIR measurements we show that AL and AO molecules are chemically bound to the surface of the NPs. By TGA measures we calculate the number of functionalized molecules. In the case of NPs coated with AL and AO were 1974 and 1486, respectively. References [1] Gupta, A.K., Gupta, M., Biomat. (2005) 26, 3995. [2] Kas, R., Sevinc, E., Topal, U., Acar, H.Y., J. Phys. Chem. (2010) 114, 7758. [3] Tsedev Ninjbadgar, et al, Solid State Sciences 6, (2004) 879–885. [4] Katerina Kluchova et al. Biomaterials 30 (2009) 2855–2863.
T05‐ Catalysis, Corrosion and Environment 24
T05: PHOTOCATALYTIC EFFECT AND MÖSSBAUER STUDY OF IRON TITANIUM SILICATE GLASS PREPARED BY SOL-GEL METHOD Y. Takahashi1*, S. Kubuki1, K. Akiyama1, K. Sinkó 2 and T. Nishida3 1Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi-Oji, Tokyo 192-0397, JAPAN 2Institute of Chemistry, Faculty of Science, Eötvös Loránd University, Pázmány P.s. 1/A, Budapest 1117, 25 Figure 1. XRD patterns of FSxTi with 'x' of (A) 10 and (B) 40 annealed at (a) 400 oC and (b) 1000 oC for 3h. 102 100 98 96 94 92 90 100 95 90 85 (A-a) (A-b) (B-a) (B-b) Figure 2. FeMS of FSxTi with 'x' of (A) 10 and (B) 40 annealed at (a) 400 oC and (b) 1000 oC for 3h. HUNGARY 3Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN *Corresponding author, e-mail: takahashi-yusuke3@ed.tmu.ac.jp Keywords: photocatalyst, silicate glass Topic: T05- Catalysis, Corrosion and Environment 1. Introduction Anatase type TiO2 is well known as a photocatalyst activated by the UV light [1]. It will be more effective to develop photocatalysts which show their activity under visible light irradiation. Recently, Takahashi et al. reported that 50Fe2O3·50SiO2 (in mass %) glass had photocatalytic activity under the visible light [2]. This result implies that iron silicate glass might be a practical photocatalyst with high efficiency. In this study, we report a relationship between local structure and visible light activated photocatalytic effect of iron titanium silicate glass prepared by sol-gel method. 2. Experimental Iron titanium silicate glasses with a composition of 50Fe2O3•(50-x)SiO2·xTiO2 (in mass %, x = 10-40, abbreviated as FSxTi) were prepared by sol-gel method. Reagent chemicals of Si(OC2H5)4, Fe(NO3)3•9H2O, Ti(OCH(CH3)2)4, HNO3, and C2H5OH were poured into a beaker and well mixed for 2 h at RT. After having been agitated by reflux-heat method at 80 oC for 2 h, the solution was poured into a glass vial and dried at 60 oC for 3 days to obtain dark brown gel samples. The samples were annealed between 400 and 1000 oC for 3 h in air. For the structural characterization, 57Fe-Mössbauer spectra (FeMS) were measured by a constant acceleration mode with a source of 57Co(Rh) with -Fe as a reference and X-ray diffractmetry (XRD) was carried out at 2θ between 10° and 80° with an interval and scanning rate of 0.02° and 5° min-1, respectively. X-ray with the wavelength of 1.54 Å generated by Cu filament was targeted by electron accelerated by 300 mA and 50 kV. 3. Results and Discussion As shown in Figs. 1 (A-a) and (B-a), XRD patterns of FSxTi with x of 10 and 40 annealed at 400 oC showed halo patterns due to amorphous structure, while intensive diffraction peaks attributed to crystalline phases of Fe2TiO5, -Fe2O3 and TiO2 were observed when annealed at 1000 oC (Figs. 1 (A-b) and (B-b)). FeMS of FS10Ti annealed at 1000 oC for 3 h showed a sextet with  of 0.38 mm s-1,  of - 0.22 mm s-1and int of 50.6 T due to α-Fe2O3 and a doublet with  of 0.38 mm s-1 and  of -10 -5 0 5 10 Velocity / mms-1 -10 -5 0 5 10 Velocity / mms-1 105 100 95 90 85 80 100 98 96 94 92 90 0.76 mm s-1 due to Fe2TiO5 (Fig. 2 (A-b)). - Fe2O3 could not be detected from the XRD pattern and the FeMS of FS40Ti annealed at 1000 oC. These results indicate that the kinds and fraction of crystalline phases precipitated in FSxTi can be controlled by the annealing conditions and the chemical composition. The photocatalytic effect of FSxTi is presented on the day of the conference. References [1] A. Fujishima, K. Honda, Nature 238 (1972) 37-38. [2] Y. Takahashi, S. Kubuki, K. Akiyama, K. Sinkó, E. Kuzmann, Z. Homonnay, M. Ristić, T. Nishida, Hyperfine. Interact. 226 (2014) 747-753
T06‐ Chemical Applications, Structure and Bonding 26
T06: 57Fe-MÖSSBAUER STUDY OF ZIRCONIA CONTAINING IRON VANADATE CLYSTALLIZED GLASS WITH HIGH ELECTRICAL CONDUCTIVITY K. Matsuda1, S. Kubuki1*, K. Akiyama1 and T. Nishida2 1 Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi-Oji, Tokyo 192-0397, JAPAN. 2 Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN. *Corresponding author: e-mail: kubuki@tmu.ac.jp Keywords: vanadate glass, electron hopping, heat-treatment, monoclinic vanadium-zirconia, beta-vanadium bronzes Topic: T06- Chemical Applications, Structure and Bonding 100 98 96 100 98 96 27 Introduction Vanadate glass is known as a semiconductor with the electrical conductivity () of 10-7-10-5 S cm-1 due to 3d electron (polaron) hopping from VVI (or VIII) to VV [1]. A drastic increase in  of up to 100 Scm-1 was observed for barium iron vanadate glass, BaO-Fe2O3- V2O5 caused by heat treatment (HT), which has a registered trademark of ‘NTAglassTM’ [2]. This unique electrical property shows that vanadate glass will be a good candidate for electrode of secondary batteries. In order to find a vanadate glass with higher , we have investigated several vanadate glasses. In the present study, we report a new conductive vanadate glass containing ZrO2 with high  value without HT. Experimental A new vanadate glass with the composition of xZrO2･ 10Fe2O3･(90−x)V2O5 (x=0-30), abbreviated as xZFV, was prepared by a conventional melt-quenching method under the melting temperature and time of 1200-1400 oC for 1h. For comparison, another vanadate glass with the composition of xZrO2･(20- x)CaO･10Fe2O3･70V2O5 (x=0-20), abbreviated as xZCFV, was prepared under the same condition. Isothermal heat treatment was performed at 500 oC for 100 min in air. 57Fe-Mössbauer spectra were measured by constant acceleration method. 57Co(Rh) and -Fe were used as a source and a reference, respectively. Measurements of  were carried out by DC four-probe method. Results and Discussion Two doublets with isomer shift () and quadrupole splitting () of 0.42±0.01 and 0.29±0.01 mm s-1, 0.34±0.03 and 1.48±0.06 mm s-1 were observed from the 57Fe- Mössbaeur spectrum of heat-treated 20ZFV glass, respectively of which is ascribed to FeIII2VV4O13 and an amorphous FeIII-VIV-O phases [3] (Fig. 1(a)). On the other hand, three paramagnetic doublets with and  of 0.39±0.01 and 0.33±0.04, 0.40±0.01 and 0.65±0.04, and 0.32±0.01 and 1.12±0.03 mm s-1 were observed from 0ZCFV glass (Fig. 1(b)), which is ascribed to FeIIIVVO4 [4]. These results may suggest that when a glass contained few network-modifiers (NWM), iron ion partially reduces vanadium from VV to VIV. (a) (b -4 -3 -2 -1 0 1 2 3 4 Velocity / mm-1s Figure 1. 57Fe-Mössbauer spectra of (a) 20ZFV and (b) 0ZCFV heated at 500 oC for 100min. A gradual increase in was observed from 6.3×10-5 to 2.9×10-3 S cm-1 with increasing ZrO2 content from 0 to 30 mol%. However, the drastic increase in due to HT, which could be observed in 0ZCFV, did not occur for xZFV glass. It is concluded that introduction of zirconia into vanadate glass results in higher conductivity without HT. In addition, we found that it is favorable for vanadate glass to contain less than 20 mol% of Ca2+ for the drastic increase in caused by HT. References [1] N.F. Mott, Adv. Phys. V. 16 No.61 (1967) 49 [2] T. Nishida, Jpn. Patent (2006) No. 3854985. [3] A. Brückner, G.-U. Wolf, M. Meisel, R. Stösser, H. Mehner, F. Majunke and M. Baerns, J. Catal. V. 154 (1995) 11 [4] S. Kubuki, K. Matsuda, K. Akiyama and T. Nishida, J. Radioanal. Nucl. Chem. V. 299 (2014) 453
T07‐ Industrial Applications 28
T08‐ Magnetism and Magnetic Materials 29
T08: CORRELATION BETWEEN MILLING TIME OF POWDER, AND THE TEMPERATURE OF SUBSTRATE ON THE PROPERTIES OF NdFe THIN FILMS Y.A. Rojas Martínez, D. Oyola Lozano, H. Bustos Rodríguez Department of Physics, University of Tolima, A.A. 546, Ibagué, Colombia *Corresponding author: e-mail: yarojas@ut.edu.co Keywords: Mössbauer spectrometry, Thin films, Mechanical alloy Topic: T08- Magnetism and Magnetic Materials In this study we report the structural and magnetic properties, obtained by 57Fe Mössbauer spectrometry (MS) and X-ray diffraction (XRD), and Physical Properties Measurement System (PPMS), of amorphous rare-earth transition metal alloys of compositions Nd0.257Fe0.743 prepared by mechanical alloying during 12, 24, and 48 hours to study the influence of the milling time of powders. The films were prepared by DC sputtering technique deposited on Kapton substrate, at substrate temperature varying at 77°K,300°K, 450°K, To study the influence of the temperature substrate in their magnetic and structural properties. The X-rays results show that the α-Fe and amorphous phase in all the samples are present. The first decreases while the second one increase, with increase of the milling time and the substrate temperature, respectively. Mossbauer spectrometry results show that the amorphous phase in samples are ferromagnetic and appears as a hyperfine field distribution and a broad doublet. When the milling time and the substrate temperature increases, the paramagnetic contribution increase too. 30
T08: IN γ-Fe2MnGa COMPOUND DO Fe AND Mn ORDER MAGNETICALLY AT THE SAME TEMPERATURE? DO THEY COUPLE PARALLEL OR ANTIPARALLEL AT LOW TEMPERATURES? Edson Caetano Passamani Depto de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, ES, Brazil Heusler alloys (HAs) are generically represented by the stoichiometric X2YZ formula, where X and Y atoms are, in principle, d-elements with more than half-filled and less than half-filled shells, respectively and Z are atoms with sp-shell electrons. This series of compounds has potential for technological application including spintronics devices. They usually stabilize at room temperature, either with L21-type (Fm3m – number 225) full Heusler alloy (HA) or with C1b-type (F-43m) half-HA structure. Specifically, for the Fe2MnGa HA there are several controversies reported in literature; either related with its crystal structure or with its magnetic state at high and low temperatures (above 300 K and below 200 K). According to first principles calculations, Fe2MnGa HA should have the stable L21-type structure, as typically found in most of full HAs. However, it was recently reported the L12-type as its stable configuration, determined by electronic calculation. Experimental results seem also to be contradictory from the structural viewpoint because the samples are no single crystalline phase. From magnetic viewpoint, a ferromagnetic (FM) state is expected to be the ground state for the L21-type as well for the L12-type structure; a ferrimagnetic (FI) configuration is 0.02 eV high in energy. An additional controversy is related to the existence of exchange bias (EB) effect, which is attributed to an antiferromagnetic (AF) state that appears at low temperatures. However, there is no direct proof for a coexistence of FM and AF states in this material, except for the presence of the loop shifting effect at low temperatures. Then, as the γ-Fe2MnGa HA has iron as a natural constituent, 57Fe Mossbauer spectroscopy could be a suitable method to investigate Fe environment and its magnetic state, considering that Mn atoms govern the alloy magnetism. Thus, in this work, bulk and local magnetic properties of the single phase polycrystalline γ-Fe2MnGa Heusler alloy have been studied in a broad temperature range and under high applied magnetic fields using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. X-ray diffraction data of the γ-Fe2MnGa alloy indicate stabilization of a L12-type structure and no structural phase transformation induced by thermal effect. While magnetization experiments have shown that the Mn sublattice is ferromagnetic well above 300 K, 57Fe Mössbauer spectroscopy indicates that Fe-sublattice orders magnetically at 200 K and couple antiparallel with Mn sublattice. This ferrimagnetic state is responsible for the magnetization reduction in low temperatures observed at low temperature. Due to high magnetic anisotropy of this material, a large vertical (magnetization-axis) and horizontal (field-axis) magnetization loop shift effects are observed in field-cool process for fields up to 5T, consequently they cannot be purely attributed to the exchange bias effect, as reported in literature for this Heusler compound. 31
T08: MAGNETIC PROPERTIES OF TWO CORE/SHELL NANOPARTICLES COUPLED VIA DIPOLAR INTERACTION W. R.Aguirre-Contreras1,*, and A.M. Schönhöbel1 1Grupo de Metalurgia y Transiciones de Fase, Facultad de Ciencias Naturales y Exactas, Universidad del Valle. Cali, Colombia *Corresponding author: e-mail: william.aguirre@correounivalle.edu.co Keywords: Magnetic core/shell nanoparticles, Monte Carlo simulation, Metropolis algorithm, dipolar interaction, Ising Model Topic: T08- Magnetism and Magnetic Materials We have used Monte Carlo simulations by Metropolis algorithm to study the magnetic properties of two identical core/shell nanoparticles with spherical shapes. A three-dimensional Ising Model with ferromagnetic (antiferromagnetic) nearest-neighbor couplings for core (shell) has been used on a body-centered cubic lattice and we have considered that nanoparticles are coupled by dipolar interactions. Zero-field cooling simulations were performed to obtain magnetization, susceptibility and Edward-Anderson factor as a function of dimensionless temperature. We also present the phase diagram as a function of the distance between nanoparticles and radii. References [1] A. Weizenmann and W. Figueiredo. Int. Journ. of Mod. Phys. C, V. 23(08) (2012) 1240006–1 [2] A. Weizenmann and W. Figueiredo. Phys. A, (2010) 389 [3] Liu W, Zhong W, Du YW., J. Nanosc. Nanotechnol. 8(6) (2008) 278 [4] D. Kechrakos and K. N. Trohidou. Appl. Phys. Lett. 81 (2002) 4574 32
T08: MÖSSBAUER AND STRUCTURAL STUDY OF ALLOYS Fe1-XVX OBTAINED BY MECHANICAL ALLOYING Dagoberto Oyola Lozano, Yebrayl Antonio Rojas Martínez, Humberto Bustos Rodríguez 1Department of Physics, University of Tolima, A.A. 546, Ibagué, Colombia *Corresponding author: e-mail: doyola@ut.edu.co Keywords: Mechanical Alloying, Mössbauer Spectroscopy, Laves phase Topic: T08- Magnetism and Magnetic Materials In the present work we studied the structural and magnetic properties of milled powders to 12, 48 and 72 hours of the Fe1-xVx with x= 0.1, 0.3, 0.5 and 0.7 obtained by mechanical alloying. The samples were characterized by Mössbauer spectroscopy and, X-ray diffraction. For times all of milling results Mössbauer spectra reveal that the samples show a behavior paramagnetic for x>0.5, and its pattern of X-ray diffraction indicates the presence of the Fe, V and FeV phases. For times greater than 48 hours of milling Fe1-xVx system with x>0.7 tends to an amorphous structure. 33
T08: MÖSSBAUER INVESTIGATIONS ON THE DESORBTION OF HYDROGEN AND HYDROXYL FROM THE IRON OXIDE NANOPARTICLES L. Herojit Singh, S. S. Pati, A. C. de Oliveira and V. K. Garg Institute of Physics, University of Brasília, 70910-970 Brasília, DF, Brazil *Corresponding author: e-mail: loushambam@gmail.com Keywords: Mössbauer spectrum, reduction, topotactical transformation Topic: T08- Magnetism and Magnetic materials 34 Magnetite (Fe3O4) due to its unique magnetic properties, it plays an important role in biological applications such as hyperthermia, gene targeting etc. Stoichiometry of magnetite dictates the magnetism of magnetite. Iron oxide nanoparticles were synthesized through precipitation of FeSO4.7H2O in the presence of NaOH maintaining the pH value of 11. XRD of the as prepared nanoparticles confirmed the single phase formation of Fe3O4 having crystallite size of 60 nm as derived using Debye Scherer formula. Mössbauer spectra of the as prepared nanoparticles and after subsequent thermally treated at various temperatures at 10-6 mbar are depicted in Fig 1. These spectra could be resolved into four subspectra. (a) IS = 0.68 mm/s ,QS = 0.03 mm/s, absorption 47%, Hint = 453 kG corresponds to Octahedral site of Fe3O4 (b) IS = 0.29 mm/s ,QS = 0.03 mm/s, absorption 26 %, Hint = 488 kG corresponds to tetrahedral site of Fe3O4 (c) The third subspectra with an area of 4 % corresponds to goethite (α-FeOOH) and (d) the fourth component with 23 % area, Hint of 464 kG, QS = 0.14 mm/s and IS = 0.33 mm/s. corresponds to hematite (α-Fe2O3) The presence of hematite could not be observed by XRD, because thermal treatment altered the stoichiometry of Fe3O4 with fine nanoparticles. The heat treatment at 423K reduced the octahedral component to 37 % and the tetrahedral part increased to 38%. Surfaces with defects such as oxygen vacancies dissociates from H2O that came into contact into H+ and OH-that got adsorbed resulting to hydrogenated surface. The dissociated H+ and OH- could not recombine due to the Jahn-Teller distorted surface that could kinetically hinder recombinative desorption. Mild heat treatment desorbs the H+ and OH– driving away oxygen from the particles. Therefore the reduction of α-FeOOH to off-stoichiometric magnetite take place at 423 K and in the process some fraction of magnetite got oxidized leading to decrease of octahedral fraction by 10 %. However thermal treatment at 423 K is not sufficient to drive away oxygen from the non-cubic fraction and thus remains unchanged. Increase in thermal treatment temperature to 523 K reduces the non-cubic to off-stoichiometric magnetite. Fig1. Mössbauer spectra of the nanoparticles and the subsequent treated at various temperatures. Further increase in the temperature i.e. at 523 K reduces α-Fe2O3 and α-FeOOH to off-stoichiometric magnetite. The Mössbauer spectra of the nanoparticles after subjecting to 773 K are resolved into Fe3O4 and 13 % γ-Fe2O3. As the temperature increases from a 773 K temperature the H and OH are desorbed from the surface of the nanoparticles causing recombination resulting in diminution of the rate of reduction of the particles. Further increase in the temperature (above 873 K) the adsorbed H and OH no more acts as the reducing agent therefore topotactical transformation of α-FeOOH to α-Fe2O3 takes place and the α-Fe2O3 nucleates to larger particles experiencing the hyperfine field of a bulk α-Fe2O3. Acknowledgements: This work was supported by CAPES project A 127-2013; LHJ and SSP thankfully acknowledge post doctoral fellowships.
T08: MÖSSBAUER STUDY OF ALLOYS Fe67.5Ni32.5, PREPARED BY ALLOY 35 Fe67.5Ni32.5 Fe67.5Ni32.5 without sieve -8 -6 -4 -2 0 2 4 6 8 1.00 0.98 0.96 0.94 1.01 1.00 0.99 0.98 0.97 0.96 1.00 0.98 0.96  m RT Mφssbauer spectra of the MA Fe67.5Ni32.5 samples milled for 10 h. relative transmission [%] relative transmission [%] m m Relative transmition [%] -8 -6 -4 -2 0 2 4 6 8 0.94 V[mm/s] MECHANICAL E.D. Benítez Rodríguez1, H. Bustos Rodriguez1, D. Oyola Lozano1, Y. A. Rojas Martínez1 y G.A. Pérez Alcázar2 1Department of Physics, University of Tolima, A.A. 546, Ibagué, Colombia 2) Instituto Nacional de Investigaciones Nucleares, Departamento de Química, Apdo. Postal 18-1027, Col. Escandón, Deleg. M. Hidalgo, C. P. 11801, México. D. F., México. *Corresponding author: e-mail: edbenitezr@ut.edu.co, hbustos@ut.edu.co Keywords: Mechanical alloying, X-Ray Diffraction, FeNi alloys, Mössbauer Spectrometry Topic: T08- Magnetism and Magnetic Materials We present the study Mössbauer of the system Fe67.5Ni32.5, prepared by mechanical alloying (MA). The structural, electronic and magnetic properties of alloys were analyzed using the techniques of x-ray diffraction (XRD), spectroscopy Mössbauer (MS) and PPMS (Physical Properties Measurement System), respectively. Samples are prepared with powders of iron and nickel in high purity (99.99%), is the respective stoichiometry of powders and powders in a planetary mill of high energy, alloy during a period of 10 hours with a 20: 1 ratio, from mass to mass of dust balls. Alloys are then sieved in different mesh: 18, 35, 60, 120, 230, 400 y 500 which are respectively equivalent a: 1mm, 500 μm, 250 μm, 125 μm, 63 μm, 38 μm y 25 μm. Mössbauer spectra in all alloys present a ferromagnetic behavior (see figure 1). In the graphs ZFC and FC, apparently exists in unscreened spin glass transition below 50K, which is reached to notice a bit in sample sizes between 63 and 125 micron and disappears for smaller sizes than 25 microns. This means that this phase is related to the larger particles. Besides the curve FC as low temperature is nearly constant for the first two and it may be due to magnetic dipole interaction is less intense for small particle as in this FC curve increases at low temperatures.
T08: SPIN DYNAMICS IN COEXISTING ANTIFERROMAGNETIC AND SPINGLASS STATES OF MULTIFERROIC LEAD PEROVSKITES S. Chillal1, F.J. Litterst2,4 *, S.N. Gvasaliya1, T. Shaplygina3, S.G. Lushnikov3, J.A. Munevar4, E. Baggio Saitovitch4 and A. Zheludev1 1 ETH Zürich, Laboratory for Neutron Scattering and Magnetism, 8093 Zürich, Switzerland, 2 Technische Universität Braunschweig, 38106 Braunschweig, Germany.3 Ioffe Physical-Technical Institute RAS, 194021St.Petersburg, Russia. 4Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro, Brazil. *Corresponding author: e-mail: j.litterst@tu-bs.de Keywords: multiferroics, spin dynamics, perovskites, Mössbauer spectroscopy Topic:T08- Magnetism and Magnetic Materials 0.2 0.1 0.08 0.04 0.00 36 PbFe1/2Nb1/2O3 (PFN) and PbFe1/2Ta1/2O3 (PFT) belong to the family of PbB’xB’’1-xO3 perovskites which have inherent chemical disorder at the B-site. Due to this disorder, complex magnetic phase diagrams are expected in these materials that undergo ferroelectric transitions already above room temperature. Magnetic ground states ranging from simple antiferromagnetic to incommensurate structures have been reported [1]. As recently shown for PFN and PFT via macroscopic characterization, neutron scattering and 57Fe Mössbauer spectro-scopy, both compounds reveal antiferromagnetic transitions at 145 K and 153 K, respectively, followed by a spinglass transition around 10 K, below which antiferromagnetism coexists with a spinglass [2,3]. We suggest that the mechanism which is responsible for such a non-trivial ground state can be explained by a speromagnet-like spin arrangement (Fig. (1)). Figure 1. Schematic of the coexisting antiferromagnetic spinglass phase in the ground state of PFN and PFT. Mössbauer spectroscopy reveals strongly temperature dependent broadenings (Fig. (2a,b)) of magnetic hyperfine patterns. This may originate from dynamic mechanisms and some inhomogeneous broadening. Notably, there is found an unusual increase of the mean magnetic hyperfine field below 50 K (Fig. (2c)) that is accompanied by a decrease in the antiferromagnetic magnetic Bragg peak intensity as measured by neutron scattering (Fig. (2d)). This is indicative for the onset of magnetic freezing on the time scale of Mössbauer spectroscopy resembling earlier findings in re-entrant spinglass systems [4]. We shall present a coherent analysis of the spin dynamics and its temperature dependent development along the different magnetic regimes, as probed by 57Fe. 50 40 30 20 10 0 7500 5000 2500 Figure 2. a), b) The distribution of hyperfine fields in PbFe1/2Nb1/2O3 at 4K and 30K, c) temperature dependent mean magnetic hyperfine field at the Fe3+ ion as observed by Mössbauer spectro-scopy, d) AF Bragg peak intensity measured by neutron scattering at wave vector (½, ½, ½) References [1] G.A. Smolenskii and I.E. Chupis, Sov. Phys. Usp. 25 (1982) 475. [2] S. Chillal, et al., Phys. Rev. B 86 (2013) 220403R. [3] S. Chillal, et al., Phys. Rev. B 87 (2014) 174418. [4] R.A. Brand, et al., J. Phys. F 15 (1985) 1987, and references given there Fe3+ Nb5+ Φ 0 50 100 150 200 250 300 0 Temper ature (K) Intensity (a.u.) QAF=(1/2, 1/2, 1/2) <Bhf> (T) b d 0.0 -20 0 20 40 60 80 Probability 4 K Bhf (T) 30 K a) b) c) d)
T08: STUDY OF STRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF Fe DOPED, Co DOPED, AND Fe-Co CO-DOPED ZnO J.J. Beltrán1*, J.A. Osorio1, C.A. Barrero1 and A. Punnoose2 1Grupo de Estado Sólido, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia 2 Department of Physics, Boise State University, Boise, Idaho 83725-1570, United States *Corresponding author: E-mail address: jjbj08@gmail.com Keywords: Diluted magnetic semiconductors, ZnO, Mössbauer spectra. Topic: T08-Magnetism and Materials Magnetic. Several works have reported ferromagnetic (FM) behavior in Fe doped, Co doped and Fe- Co co-doped ZnO systems, but there are a lot of controversies about the observed ferromagnetism. Then, careful structural and magnetic investigations with high quality single-phase 37 samples are desired to investigate in detail this controversy. In this work, we explore the effect of Fe doping, Zn1-xFexO, Co doping, Zn1-xCoxO and Fe-Co co-doping Zn1-xFexCoxO with x =0.0, 0.01, 0.03 and 0.05 on the crystallographic, structural, optical and magnetic properties of zinc oxide nanoparticles, prepared by Sol-Gel method. These fine powders of the as-obtained product, after being annealed at 550 oC for 1h, were characterized by X ray diffraction (XRD), optical absorption, X-ray photoelectronic spectroscopy (XPS), electron paramagnetic resonance (EPR) at RT and as a function of temperature, RT 57Fe Mössbauer spectroscopy and magnetic measurements as a function of applied magnetic field and as a function of temperature [1, 2]. The XRD patterns showed that the formation of hexagonal wurtzite ZnO crystal structure in all samples was discerned as the only single phase. Optical absorption results displayed that Co doped ZnO samples exhibited smaller band gaps (Eg) than Fe doped ZnO samples and that Fe-Co co-doped ZnO nanopowders showed intermediate values. In RT 57Fe Mössbauer spectra for all Zn1-xFexO samples only paramagnetic signals were detectable, ascribed to Fe3+. For x=0.05 the introduction of a third doublet was clearly necessary, which was attributed to spinel phase ZnFe2O4. In contrast, the spectra of Zn1-xFexCoxO sample did not show this third doublet, suggesting that Co ions might be preventing the formation of ZnFe2O4. XPS and EPR results showed only Co2+ ions for Zn1-xCoxO samples with x =0.01 and 0.03, and with further doping, mixed valence of Co2+ and Co3+ were evidenced, while in Fe-Co co-doped ZnO samples this mixed valence was observed for all doping concentration. Additionally, variable temperature EPR studies in Zn1- xFexCoxO suggested that some Co2+ ions are weakly FM coupled. Interestingly, pure ZnO sample exhibited very weak ferromagnetism, which might arise from the presence intrinsic defects that can become magnetic. The RT M vs H data of all doped and co-doped samples exhibited a linear component superimposed on a saturating FM-like magnetization. The FM character of Zn1-xFexO and Zn1-xCoxO were similar to each other, but increased compared with that of undoped ZnO. Now, Zn1-xFexCoxO samples showed higher FM behavior in comparison to the presence of only one of these cations. We deem that more probably the main role of Fe3+ ions in ZnO structure may be related to the formation of defects on the surface region, while Co ions have higher effect in its electronic properties. In Zn1-xFexCoxO the magnetic signal has been interpreted in terms of the charge transfer ferromagnetism involving mixed valence ions, most likely Co3+−Co2+ in addition to changes in the electronic structure associated with the presence of defects in the nanoparticles. The study suggested that the simultaneous introduction of Fe and Co ions in ZnO lattice has a strong synergistic effect because they eliminated the formation of the ZnFe2O4 and gave the strongest ferromagnetic signal in comparison to the presence of only one of these cations. References [1] J.J. Beltrán et.al J. Phys. Chem. C 118 (2014) 13203−13217. [2] J.J. Beltrán et.al J. Appl. Phys. 113 (2013) 17C308.
T08: SYNTHESIS AND CHARACTERIZATION OF NixCo1-xFe2O4 Nanoparticles P.M.A. Caetano1, P. R. Matos1, A. S. Albuquerque1, L.E. Fernadez-Outon2, J.D. Ardisson1 and W.A.A. Macedo1 1Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Serviço de Nanotecnologia, Belo Horizonte, Minas Gerais, Brasil. 2 Universidade Federal de Mina Gerais (UFMG), Departamento de Física, Belo Horizonte, Minas Gerais, Brasil. *Corresponding author: e-mail: patriciamacaetano@gmail.com Keywords: Ferrite, magnetism, nanostructure Topic: T08 - Magnetism and Magnetic Materials Nanostructured magnetic systems have been intensively investigated due to the different behavior of the materials at least one of their dimensions is in the nanometer range1. Among the nanostructured materials, ferrites, iron oxides of the type MFe2O4 (M = divalent metal ion) have been widely studied due to their magnetic properties, some of which are of great potential for application in the manufacturing of sensors with high sensitivity, e.g. for biomedical applications, such as hyperthermia, among others2,3. The present work consists in the synthesis and the investigation of structural and magnetic properties of nanostructured NixCo(1- x)Fe2O4 (with x = 0, 0.25, 0.5, 0.75 and 1.0) for hyperthermia applications. Ferrite nanoparticles were synthesized by coprecipitation and calcined at 700 °C, for 2 h. The nanoparticles were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy and vibrating sample magnetometry (VSM). The capacity of heat generation of the ferrites, dispersed in deionized water when submitted to an AC field (198 kHz and 220 Oe), was investigated. The XRD patterns, Fig.1 (a), showed well defined peaks, indicating the formation of the desired spinel phase. The average particle size was about 30 nm as calculated from Scherrer's formula. The magnetization curves showed that the coercivity and saturation magnetization increase due to the increase of cobalt content, as can be seen in Table 1. Table 1 – Saturation magnetization and coercivity of the ferrite samples Saturation magnetization (MSat) and Coercivity (Hc) NixCo1-xFe2O4 X=1 X=0.75 X=0.5 X=0.25 X=0 MSat (emu/g) 20 42 49 63 66 Hc (Oe) 150 490 920 1000 1413 38 (b) Figure 1 (a) XRD patterns and (b) Mössbauer spectra of ferrite samples studied. Mössbauer spectra of the ferrite samples, measured at 80 K, are shown in Fig.1 (b). The spectra were fitted with two sextets referring to the Fe3+ ions present in tetrahedral and octahedral sites. Samples with higher content of Ni showed significant heating, reaching temperatures higher than 50 oC after 30 min under an alternating magnetic field due to both Brownian motion and magnetisation reversal. Our results indicated that, the control of Ni and Co content, and the nanoparticle concentration, would allow for the tailoring of the heating capabilities of these ferrites being a promising material for several applications, such as hyperthermia. This work is supported by CAPES (PNPD), CNPq and FAPEMIG. References [1] Q.A. Pankhurst, J.Connolly, S.K. Jones, J. Dobson, J. Phys. D: Appl. Phys., 36, R167 (2003). [2] C.A. Sawyer, H. Habib, K. Miller, K.N. Collier, C.L. Ondeck, M.E. McHenry, J. Appl. Phys. 105, 07B320 (2009). [3] B. D. Cullity, Introduction to Magnetic Materials (Addison-Wesley, London, 1972).
T08: SYNTHESIS OF SILVER -COATED MAGNETITE NANOCOMPOSITE FUNCTIONALIZED BY AZADIRACTHA INDICA J. L. López1, C. Carioca Fernandes1, D. M. Sá Oliveira1, M. Amorim Lima1, J. H. Dias Filho2, R. Paniago3 and K. Balzuweit3 1Centro de Ciências Biológicas e da Natureza, Núcleo de Física, Universidade Federal do Acre, Rio Branco, AC 69915-900, Brazil. 2) Departamento de Ciências Exatas, Universidade Estadual de Montes Claros, 39.401-089, Minas Gerais, Brazil. 3) Departamento de Física, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Brazil. *Corresponding author: e-mail: jorge0503@gmail.com Keywords: Nanoparticles,functionalization, Topic: T08- Magnetism and Magnetic Materials 39 Magnetic nanoparticles of iron oxides such as magnetite (Fe3O4) were coated with silver and then functionalized with extract of Azadirachta indica (Neem) forming a composite for use as non-toxic for the control of insect pests magnetic boots. The development of these composites requires a detailed study of the synthesis and magnetic properties of the functionalized nanoparticles to be used as an insecticide. In agriculture Azadirachta indica is used as a natural pesticide [1] and it was our interest to develop functionalized composite magnetic nanoparticles to combat Spodoptera frugiperda which is a pest of major importance in maize by reducing up to 34% crop productivity. This nanobiotechnological insecticide could also be applied to other type of pest. Magnetic fluids based on Fe3O4 has been synthesized using the condensation method by coprecipitating aqueous solutions of FeSO4, HCl and FeCl3, oleic acid mixtures in NaOH at room temperature [2-3]. Coating of Fe3O4 magnetic nanoparticles was achieved by dispersing this magnetite in AgNO3 solution containing specific amount of urea in vigorous stirring and mixture of sodium hydroxide solution and polyvinyl pyrrolidone (PVP), as stabilizer polymer, was added and finally a solution glucose was mixture. In the next step magnetite-silver core-shell nanoparticles were functionalized by Azadirachta indica. Samples with an average particle diameter ~7 nm and different concentrations of extract were studied by Mössbauer spectroscopy and dc magnetization measurements in the range of 4.2–250 K. The saturation magnetization (Ms) at 4.2 K were determined from M vs 1/H plots by extrapolating the value of magnetizations to infinite fields, to 3 - 5 emu/g and coercivity to 20- 50 Oe. The low saturation magnetization value was attributed to spin noncollinearity predominantly at the surface. From the magnetization measurements a magnetic anisotropy energy constant (K) between 1.3 - 3 ×104 J/m3 were calculated. Fe3O4 functionalized spectra at room temperature showed a singlet due to superparamagnetic relaxation and two sextets at low temperature. The line form in spectra Mössbauer vary with the temperatures it were simulated using a model of superparamagnetic relaxation of two levels (spin ½) and theory stochastic. It was taken into account that a distribution of the size of the particles that obeys a log-normal. References [1] A. H. Varella Bevilacqua H., B. Suffredini, M.M. Bernardi, Rev. Inst. Ciências da Saúde; 26(2) (2008)157. [2] J. L. López, J.H. Dias Filho, R. Paniago, H. – D. Pfannes, K. Balzuweit, Revista ECIPerú, 10(2) (2014) 5. [3] Y.M. Wang, X. Cao, G.H. Liu, R.Y. Hong, Y.M. Chen, X.F. Chen, H.Z. Li, B.Xu, D.G. Wei, J. Magn. Magn, Mater. 323 (2011) 2953.
T09‐ Multilayers, Thin Films and Artificially Structured Materials 40
T10‐ Physical Metallurgy and Materials Science 41
T10: MÖSSBAUER AND XRD CHARACTERIZATION OF THE PHASE TRANSFORMATIONS IN A Fe-Mn-Al-C AS. CAST ALLOY DURING TRIBOLOGY TEST J. Ramos1, J. F. Piamba2, H. Sánchez3, and G.A. Pérez Alcázar2* 1Universidad Autónoma de Occidente, Km. 2 vía Jamundí, Cali, Colombia 2Universidad del Valle, Departamento Física, A.A. 25360, Cali, Colombia 3Universidad del Valle, Escuela de Materiales, A.A. 25360, Cali, Colombia *Corresponding author: e-mail: gpgeperez@gmail.com Keywords: Fermanal steels, DRX, Mossbauer spectrometry, tribology Topic: T10- Physical Metallurgy and Materials Science 42 In this study Fe-29Mn-6Al–0,9C-1,8Mo-1,6Si- 0,4Cu (%w) alloy was prepared in an induction furnace. Chemical analysis of the as-cast sample was performed by optical emission spectrometry; Pin on Disk Tribometer (ASTM G99) at room temperature was used to evaluate the mass loss. Microstructure was characterized by Optical Microscopy, Ray X Diffraction and Transmission Mossbauer Spectroscopy. The obtained microstructure of the as-cast sample is of dendritic type and its XRD pattern (not shown here) was refined with the lines of the austenite with a volumetric fraction of 99.39% and lattice parameter of 3.67 Å, and the lines of the martensite with a volumetric fraction of 0.61% and lattice parameters of 2.91 and 3.09 Å. 1,00 0,95 0,90 0,85 exp total fit1 -9 -6 -3 0 3 6 9 relative transmission V [mm/s] Figure 1. Mossbauer spectrum of the as-cast sample. Fig. 1 shows the Mossbauer spectrum of the as-cast sample and it was fitted with a singlet which corresponds to the austenite. After the tribology test, using a charge of 3N, the surface of the sample was examined and in Fig. 2 its XRD pattern is shown. The refinement of this pattern was performed with the lines of the austenite phase with a volumetric fraction of 97.89% and lattice parameter of 3.67 Å, and also the lines of the martensite with a volumetric fraction of 2.21% and lattices parameters of 2.90 and 3.09 Å. Figure 2. XRD pattern of the surface of the as-cast sample after the wear test. Finally Fig. 3 shows the Mossbauer spectrum of the surface of the as-cast sample after the wear test. 1,00 0,95 0,90 0,85 exp total fit1 fit2 fit3 fit4 fit5 -12 -9 -6 -3 0 3 6 9 12 relative transmission V [mm/s] Figure 3. Mossbauer spectra of the surface of the as-cast sample after the wear test This spectrum was fitted with a big paramagnetic site with similar parameters of that shown in Fig. 1, which corresponds to the austenite phase of Fe and a hyperfine magnetic field distribution which is associated to the disordered martensite which appear in the surface as a consequence of the wear process. The martensite is the responsible of the hardening of the material.
T10: STRUCTURAL STUDY ON Li2Fe1-xNixSiO4 J.A. Jaén1, M. Jiménez2, E. Flores3, A. Muñoz2, J.A. Tabares4, and G.A. Pérez Alcázar4 1Depto. de Química Física, CITEN, Edificio de Laboratorios Científicos-VIP, Universidad de Panamá, Panamá 2Depto. de Física, Universidad de Panamá, Panamá 3Escuela de Física, Universidad de Panamá, Panamá 4Departamento de Física, Universidad del Valle, AA 25360, Cali, Colombia *Corresponding author: e-mail: juan.jaen@up.ac.pa Keywords: Orthosilicates, Li2FeSiO4. Topic: T10- Physical Metallurgy and Materials Science Li2FeSiO4 is a promising cathode material for Li-ion 43 battery applications [1]. This material has good electrochemical activity and high cycling stability, but poor electronic conductivity and lithium ion mobility. One manner to improve the electrochemical performance is to dope with an isovalent cation [2-4]. Li2Fe1-xNixSiO4 (x=0, 0.10, 0.15, 0.20 and 0.30) samples were prepared via solid state reaction to study the effects of doping Ni on the crystal structure of the orthosilicate. The phase structure, morphology and composition of Li2Fe1-xNixSiO4 nanocrystals were investigated by X-ray diffraction (XRD), Mössbauer spectroscopy (MS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS), respectively. Mössbauer spectra are shown en Figure 1. X-ray diffraction data accompanied by Rietveld refinement and Mössbauer measurements showed that both, the pristine and doped Li2Fe1- xNixSiO4, basically crystallize in a monoclinic structure with (P21/n) symmetry. The doped materials up to 5% mol of Ni2+ retain the monoclinic structure and lattice parameter, which indicates that doping agent introduces into the structure of Li2FeSiO4 without destroying the lattice structure. There is a small increase of volume of the unit cell and slight changes in local environments around the FeO4 and SiO4 tetrahedra with increasing Ni doping. The crystallite size calculated from the Scherrer equation is about 60 nm. Some small amounts of electrochemical deleterious impurities, Fe2+ and Fe3+ phases, and unreacted Li2SiO3 are detected. Samples doped with more than 10 mol% contain some magnetic impurity of Fe-Ni alloy as a result of the reduction of the Fe2+ provided in the raw materials by residual carbon. The in situ formed carbon may enhance the electronic conductivity of the electrode, and effectively suppresses the grain growth of Li2FeSiO4 [5-7]. Magnetic measurements indicated that the lithium iron orthosilicate is a paramagnetic ceramic which becomes antiferromagnetic below 23 K. Nickel dopant does not modify the paramagnetic nature of this cathode material. Figure 1. Room temperature Mössbauer spectra of Li2Fe1-xNixSiO4 samples. References [1] A. Nytén, A. Abonimrane, M. Armand, T. Gustafsson and J.O. Thomas, Electrochem. Commun. 7 (2005), 156-160. [2] Y.H. Chen, Y.M. Zhao, X.N. An, J.M. Liu, Y.Z. Dong, Electrochim. Acta 54 (2009), 5844- 5850. [3] C. Deng, S. Zhang, S.Y. Yang, B.L. Fu and J. Ma, J. Power Sources 196 (2011), 386–392. [4] B. Shao and I. Taniguchi, J. Power Sources, 199 (2012) 278-286. [5] L.M. Li, H.J. Guo, X.H. Li, Z.X. Wang, W.J. Peng, K.X. Xiang and X. Cao, J. Power Sources 189 (2009), 45-50. [6] Z. Yan, S. Cai, L. Miao, X. Zhou and Y. Zhao, J. Alloys Compd. 511(1) (2012), 101-106. [7] Z. Yan, S. Cai, L. Miao, X. Zhou and Y. Zhao, J. Alloys Compd. 511(1) (2012), 101-106.
Posters 44
T02 CHARACTERIZATION OF NATURAL ZEOLITE CLINOPTILOLITE FOR SORPTION OF 45 CONTAMINATNS E. Xingu-Contreras1, G. García-R1, I. García-Sosa2 and A. Cabral-Prieto2(*) 1Instituto Tecnológico de Toluca, Avenida Tecnológico S/N, Fraccionamiento. La Virgen, c. p. 52149, Metepec, Estado de México, México. 2) Instituto Nacional de Investigaciones Nucleares, Departamento de Química, Apdo. Postal 18-1027, Col. Escandón, Deleg. M. Hidalgo, C. P. 11801, México. D. F., México. *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: zeolites, nanomaterials, Móssbauer. Sorption. Topic: T02- Amorphous, nanocrystal ans nanoparticles Cd contaminated rivers is one of the ambient problems that society is facing since long time ago. The traditional chemical routines produce secondary to use procedures of green chemistry [1]. In this sense present study a Mexican pretreated natural zeolite, products that the environment is further contaminates. So, new methodologies are necessary to remediate these ambient problems by trying the Clinoptilolite, with adsorbed nano crystals of Fe0 is used to remove Cr(II) in aqueous phase. The characterization of this pretreated zeolitic material, before and after the sorption process was made using X-ray diffraction (XRD), Scanned electron microscopy (SEM/EDS) and Mössbauer spectroscopy. The XRD patterns of this zeolitic material are characteristic the Clinoptilolite zeolite only. Figure 1 XRD patterns of the treated Clinoptilolite. (a) Tarjeta JCPDS, (b) natural zeolite, (c) natural zeolite with Fe0 nanoparticles. From SEM, nano particles of different size were observed ranging from 8 to 120 nm. The Mössbauer spectra of these zeolite materials may consist of a well defined quadrupole double superimposed to broad magnetic pattern. From the isothermal curves of adsorption 35 mg of Cd(II) /g of natural zeolite can be removed from aqueous media. Figure 2. SEM image of the natural zeolite with nano particles of Fe0, prepared with 0.54 g of FeCl3 6 H2O per g of natural zeolite [2]. Figure 3. Typical Mössbauer spectrum of natural zeolite with Fe0 core-shell nano particles.
The sorption of Cd(II) using natural zeolite alone removes 30 mg of Cd(II)/g, suggesting that iron nano particles may favor the removal of heavy metals more efficiently. References [1] Lázar, K., Beyer, H., Onyestyák, G., Jönsson, B., Varga, L., & Pronier, S. NanoStructured Materials, 12, (1999). 155- 158. [2] Yuvakkumar, R., Elango, V., Rajendran, V., & Kannan, N. Digest Journal of Nanomaterials and Biostructures", (2011). 1771-1776. 46
T02 NOVEL PROTOCOL FOR THE SOLID‐STATE SYNTHESIS OF MAGNETITE FOR 1.000 0.995 0.990 0.985 0.980 -12 -9 -6 -3 0 3 6 9 12 Velocity (mm/s) -10 -5 0 5 10 Velocity (mm/s) 47 MEDICAL PRACTICES D.L. Paiva, A.L. Andrade, J.D. Fabris, J.D. Ardisson, and R.Z. Domingues 1Department of Chemistry CCEB, Federal University of Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil. 2Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), 39100-000 Diamantina, Minas Gerais, Brazil. 3Laboratory of Applied Physics, Center for the Development of the Nuclear Technology, 31270-901 Belo Horizonte, Minas Gerais, Brazil. 4Department of Chemistry ICEx, Federal University of Minas Gerais (UFMG), 31270-901 Belo Horizonte, Minas Gerais, Brazil. *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: Biomedicine, Nanotechnology, Sucrose Topic: T02- Amorphous, Nanocrystals and Nanoparticles Real benefits of nanotechnology both in industrial processes and in medicine are being inimitable. Reducing sizes may significantly change some physical and chemical properties, including electrical conductivity, magnetic response, active surface area, chemical reactivity, and biological activity, relatively to the corresponding characteristics of the bulk counterpart material. The way nanoparticles are synthesized may determine their morphological uniformity, their particle sizes distribution and, as a critical feature for clinical purposes, their purity. These conditions become one of the key-issues for researchers in nanoscience and developers in nanotechnology, particularly to plan the synthesis of maghemite (-Fe2O3) or magnetite (Fe3O4) with controlled form, size in the nanoscale and magnetically induced hyperthermic behavior, if the material is to be destined to medical clinical practices. This work was devoted to the synthesis of magnetite nanoparticles by reducing the chemical oxidation state of iron (III) in a commercial synthetic maghemite. The direct solid-state chemical conversion procedure that was first used by Pereira [1] to obtain magnetite by mixing and burning a natural hematite (Fe2O3) with glucose was found unsuccessful, in the present case. Instead, the magnetite could only be effectively produced by putting the reacting mixture of the starting synthetic commercial maghemite mixed with sucrose in a furnace at 400 oC for 20 min. The after-reaction residual carbon was removed with an oxidant chemical agent to render the suitably pure magnetic oxide. The samples were characterized by Mössbauer spectroscopy; powder X-ray diffraction and Fourier transform infrared (FTIR). The 298 K-Mössbauer spectrum collected for the starting maghemite and the corresponding parameters are given in Figure 1 and Table 1. Figure 2 shows the spectrum and the corresponding parameters (Table 2) for the obtained magnetite by using a mass ratio maghemite:sucrose of 1:5. Relative transmission Figure 1. 298 K-Mössbauer spectrum for the starting commercial synthetic maghemite. Table 1: Hyperfine parameters of the fitted Mössbauer spectra recorded at 298 K. */mms-1 2/mms-1 Bhf/T RA/% 0.33 0.01 50.3 77 0.30 -0.06 48.8 13 1.0043 0.9960 0.9877 Relative transmission Figure 2. 298 K-Mössbauer spectra for the obtained magnetite after the calcinations of maghemite with sucrose.
Table 2: Hyperfine parameters of the fitted Mössbauer spectra recorded at 298 K. */mms-1 2/mms-1 Bhf/T RA/% 0.65 0.04 45.9 64 0.27 -0.02 48.9 34 *Relative to Fe. Acknowledgements: Work supported by FAPEMIG and CNPq (Brazil). JDF is indebted to CAPES (Brazil) for granting his Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. Reference [1] Pereira, MC (2009) Preparação de novos catalisadores tipo Fenton heterogeneous à base de óxidos de ferro formados em litologia de itabirito. DSc thesis. UFMG, Brazil. In Portuguese. 48
T02 MÖSSBAUER STUDIES OF POLYANILINE COATED MAGNETIC NANOPARTICLES J.C. Maciel1,2, A.A.D. 49 Merces2, M. Cabrera2, W.T. Shigeyosi3, S. D. de Souza4, M. Olzon-Dionysio4, C.A. Cardoso3 and L.B. Carvalho Jr.2 1Universidade Federal de Roraima, Boa Vista, RR, Brazil. 2Laboratório de Imunopatologia Keizo Asami, Universidade Federal de Pernambuco, Recife,PE, Brazil. 3Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, Brazil. 4 Universidade Federal dos Vales de Jequitinhonha e Mucuri, Diamantina, MG, Brazil *Corresponding author: e-mail: jackeline_maciel@hotmail.com Keywords: PANI, magnetic nanoparticles, magnetite Topic:T02- Amorphous, Nanocrystals and Nanoparticles Polyaniline (PANI) draws special attention among other conducting polymers due to the simple synthetic methodology, good environmental stability, optical activity, controllable doping [1], easy tunability of its electronic properties and high levels of electromagnetic shielding performances at microwave frequencies with a low mass by unit of surface [2]. The aim of this work is to study the structural and magnetic characteristics of polyaniline coated magnetic nanoparticles for their application as an insoluble support for enzyme immobilization. The differences in the crystalline behavior of magnetic nanoparticles and polyaniline coated magnetic nanoparticles (mPANI) are analyzed using XRD measurements. Fig. 1 shows XRD patterns for magnetic nanoparticles and mPANI. Figure 1. XRD patterns. The 2θ peaks at 18.44°, 30.30°, 35.67°, 43.37°, 53.80°, 57.35°, 62.97°, 71.43° and 74.48° are attributed to the crystal planes of magnetite. According to Yu et al. [3], the absence of the (221) reflections, corresponding to maghemite, suggests magnetite as a predominant phase. In this work, the absence of this peak was also observed. However, we cannot rule out the presence of maghemite in the samples produced, as the FTIR results, for example, suggest otherwise (Fig. 1). Fig. 2 shows the adjusted Mössbauer spectra at 298 K for magnetic nanoparticles and mPANI, where the contribution of two magnetic subspectra corresponds to Fe3+ in the tetrahedral position and [Fe3+/Fe2+] in the octahedral coordination in the spinel structure. Figure 2. Mössbauer spectra at room temperature. In Fig. 2, the presence of a doublet at the center of the spectrum can be observed. This doublet emanates from ferric iron in a non-spherical place, which perhaps comes from the rim of the iron oxide core. The Mössbauer spectrum could not be fitted with two discrete tetrahedral and octahedral sites along with a doublet because of the superposition of relaxing sextet and doublet patterns. To block the superparamagnetic relaxation effect, the Mössbauer spectrum should be recorded at a low temperature. According to Mössbauer spectra and the hyperfine parameters, it is clear that the process to obtain the mPANI does not interfere significantly with the nature of the oxide. However, a small percentage of maghemite must be present in the samples due to the oxidation process. References [1] K.R., Reddy et al., React. Funct. Polym., V (67) (2007) 943. [2] B., Belaabe et al., J. Alloy Compd., V(527) (2012) 137. [3] R.E., Vandenberghe et al., Hyperfine Interact., V(126) (2000) 247.
T02 STRUCTURAL AND MICROSTRUCTURAL CHARACTERIZATION OF THE AlFe NANOSTRUCTURED INTERMETALLIC OBTAINED BY MECHANICAL MILLING 50 R.Rocha Cabrera, M. Pillaca, C.V. Landauro, J. Quispe- Marcatoma Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima 14, Perú *Corresponding author: e-mail: jquispem@unmsm.edu.pe Keywords: Al-Fe system, nanostructuration. Topic: T2- Amorphous, Nanocrystals and Nanoparticles Nowadays, intermetallic AlFe alloys have taken attention of many researchers for their application in different branches of industry. This is due to the high corrosion resistance and low density of these systems [1]. In particular, AlFe alloys have interesting mechanical and magnetic properties, where the order or disorder in the sample is of crucial importance to define its physical behavior [2]. In this sense, the nanostructuration process gives us the possibility to change its structure and, consequently, manipulate the physical properties as function of the average grain size [3]. In the context described above, in the present work we investigate the structure and micro-structure of the nanostructured intermetallic AlFe (50 at.% Al). Solid samples were produced using the arc furnace technique under Ar-atmosphere. Subsequently, the alloys were thermally annealed at 600°C during 48 hours. The nanostructured samples were obtained by means of mechanical milling employing a high energy ball milling equipment (SPEX 8000). The obtained products were characterized by powder X-ray diffraction (XRD) and transmission Mössbauer spectroscopy (TMS). The XRD results indicate that the annealed solid samples can be indexed as a single AlFe phase. The sample milled up to 20 hours presents AlFe nano-grains with a solid solution of Al in Fe, i.e. Fe(Al). The results of TMS show that the local order around Fe sites is of the B2-type. References [1] V.N. Antonov, O.V. Krasovska, E.E. Krasovskii, Y.V. Kudryavtsev, V.V. Nemoshkalenko, B.Y. Yavorsy, Y.P. Lee and K.W. Kim, Phys. Condens. Matter 9,11227, (1997). [2] H. Wu, I. Baaker, Y. Liu, X. Wu and J. Cheng, Intermetallics 19, 1517, (2011). [1] C. Suryanayana., Prog. Matter. Sci., 46, 1 (2001).
T03 CHARACTERIZATION OF PIGMENT FROM THE TAMBO COLORADO ARCHAEOLOGICAL SITE BY MÖSSBAUER SPECTROSCOPY -10 -5 0 5 10 Velocity ( mm s-1 ) 51 A. Trujillo, E. Zeballos- Velásquez, V. Wright, M. Mejía 1Laboratorio de Arqueometría, 2Laboratorio de Cristalografía Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos. Ap. Postal 14-0149. Lima, Perú. 3 Instituto Francés de Estudios Andinos, Avenida Arequipa 4500, Casilla 18-1217, Lima, Perú. *Corresponding author: aletruj70@gmail.com Keywords: Pigments, Mössbauer spectroscopy, X-Ray Diffractometry Topic: T03- Applicationsin Soils, Mineralogy, Geology, Cements and Archaeology. The Tambo Colorado archaeological site, located on the right bank of the Pisco Valley (290 Km South of Lima), is of importance because of its monumentality, colorful and the apparent good condition, features that make it attractive to different visitors and researchers. Most of the studies about this site have been directed to make architectural records, interpretations of the function and use of areas of the site, as well as its strategic importance during the Inca conquest; interpretations of the symbolic importance of the mural paintings of the site have also been made. However, these studies do not have been articulated integrally with descriptions and records of the site, so it is considered useful to carry out an investigation involving the analysis of the nature of the materials, as well as an adequate understanding of the state of conservation of its architecture [1]. In the present work are analyzed samples of pigments from the Tambo Colorado site, using Mössbauer Spectroscopy by transmission and x-ray diffractometry, in order to study the structure of these materials. In Figure 1 are shown the Mössbauer spectrum of the sample Tambo RN. In the study of pigments containing iron, Mössbauer Spectroscopy has proven to be a useful and sensitive tool to identify the presence of iron sites that differ from one another not only in its octahedral or tetrahedral coordination but also in small deviations from the ideal geometry, in addition to the differences in their chemical environments [2]. In this sense, this research will contribute to achieve these goals, because the conservation requires a critical approach based on the definition of the main characteristics of the object to be treated, which can be achieved with a qualitative and quantitative understanding of the physico-chemical properties of the object in study [3]. 1.005 1.000 0.995 0.990 0.985 0.980 0.975 0.970 0.965 Figure 1. Mossbauer spectrum of sample Tambo RN. Relative transmission (%) References [1] Wright V. Proyecto de Investigación Tambo Colorado. Instituto Francés de Estudios Andinos. Lima (2012). [2] U, Casellato; P, Vigato; U, Russo, M, Matteini, Journal of Cultural Heritage 1 (2000) 217-232. [3] D, Hradila; T, Grygara; J, Hradilova; P, Bezdicka.. Applied Clay Science 22 (2003) 223– 236.
T03 CHEMICAL AND MINERALOGICAL ANALYSES OF PIGMENTS FROM RUPESTRIAN PAINTINGS OF THE PEDRA DO CANTAGALO I SITE, IN PIAUÍ, BRAZIL 52 Luis Carlos Duarte Cavalcante1,2,3, Heralda Kelis Sousa Bezerra da Silva1, José Domingos Fabris2,3, José Domingos Ardisson4 1Centro de Ciências da Natureza, Universidade Federal do Piauí, 64049-550 Teresina, Piauí, Brazil 2Departamento de Química, Universidade Federal de Minas Gerais, 31270-020 Belo Horizonte, Minas Gerais, Brazil 3Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), 39100-000 Diamantina, Minas Gerais, Brazil 4Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 Belo Horizonte, Minas Gerais, Brazil *Corresponding author: e-mail: cavalcanteufpi@yahoo.com.br Keywords: Archaeometry, Mössbauer spectroscopy, rupestrian art. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The rupestrian art site known as Pedra do Cantagalo I (geographical coordinates, 04° 25’ 07.7” S 41° 40’ 20.2” W) is a sandstone shelter in a countryside area of the municipality of Piripiri, state of Piauí, Brazil. The archaeological site does contain an exceptional collection of more than 1,900 rupestrian paintings, rupestrian engravings, chipped lithics, polished lithics, ceramic materials and mineral pigments (reddish ochres). The rupestrian paintings mainly represent geometric graphisms, human handprints, anthropomorphic and zoomorphic motifs, painted in yellow, black, gray, white, orangish and red of different hues [1]. The chemical and mineralogical analyses of pigments from those rupestrian paintings were made in the laboratory with (i) energy dispersive X-ray fluorescence (EDXRF); (ii) room temperature 57Fe Mössbauer spectroscopy in backscattering geometry of -rays and (iii) grazing incidence X-ray diffraction (GIXRD), intending to identify the main iron-bearing minerals composing the painting pigments. Results reveal that the red pigments of the selected paintings are essentially composed of hematite (Fe2O3)-rich materials; the yellow pigments contain goethite (FeOOH) and the black are composed of carbon, which presumably were prepared as a mixture of charcoal and hematite, but maghemite (Fe2O3) is also clearly detected (Mössbauer spectrum, Figure 1). -10 -8 -6 -4 -2 0 2 4 6 8 10 1.08 1.07 1.06 1.05 1.04 1.03 1.02 1.01 1.00 Relative Emission Doppler Velocity, v/mm s-1 Figure 1. 57Fe Mössbauer spectrum of the pigment from the black rupestrian painting (sample PCI.2009.03). The iron oxides and oxyhydroxides occur in small particle sizes, with high isomorphic substitution of different cations for iron and low crystallinity. The X-ray diffraction patterns also reveal the occurrence of quartz (SiO4), brushite (CaPO3(OH).2H2O), gypsum (CaSO4.2H2O) and KAl3(SO4)2(OH)6 (Figure 2). QC 10 20 30 40 50 60 70 80 90 100 20 16 12 8 4 54 45 36 27 18 9 0 Substrate Intensity/102 Counts 2/º (CuK) Rupestrian Painting Q Q S S S GS GS GB GB GB CGM Q QC Q Q Q QG H H H HQM H H HM HG Figure 2. GIXRD patterns for the black rupestrian painting (PCI.2009.03) and its substrate. H = hematite, αFe2O3; M = maghemite, Fe2O3; C = carbon; Q = quartzo, SiO2; B = brushite, CaPO3(OH) . 2H2O; G = gypsum, CaSO4 . 2H2O; S = KAl3(SO4)2(OH)6. From these data, the precursor clayey material containing mainly hematite was somehow heated on wood fire, during manipulation to prepare the ochre. This hypothesis may explain the appearance of maghemite in the black painting.
Reference [1] L. C. D. Cavalcante, A. A. Rodrigues. Int. J. South American Archaeology (7) (2010) 15. Acknowledgements: Work supported by FAPEMIG, FINEP, UFPI and CNPq (Brazil) (CNPq grants # 487148/2013-4; 124629/2013-0 and 305755-2013-7). JDF is indebted to CAPES (Brazil) for granting the Visiting Professorship at UFVJM under the PVNS program. The authors also thank Mr Mário da Silva Araújo Filho (CDTN) for his kind technical help on DRX data collection. 53
T03 IN‐SITU 57Fe MÖSSBAUER CHARACTERIZATION OF IRON OXIDES IN PIGMENTS OF A RUPESTRIAN PAINTING FROM THE SERRA DA CAPIVARA NATIONAL PARK, IN BRAZIL, WITH THE BACKSCATTERING MÖSSBAUER SPECTROMETER MIMOS II 54 Maria Conceição Soares Meneses Lage1, Luis Carlos Duarte Cavalcante1, Göstar Klingelhöfer2, José Domingos Fabris3,4,* 1Center of Natural Sciences; Federal University of Piauí (UFPI); 364049-550 Teresina; Piauí; Brazil. 2Institut Inorganic and Analytical Chemistry, Joh. Gutenberg-University Mainz. 55099 Mainz, Germany. 3Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM); PRPPG; Campus JK; 39100-00 Diamantina; Minas Gerais; Brazil. 4Department of Chemistry – ICEx; Federal University of Minas Gerais (UFMG); 31270-901 Belo Horizonte; Minas Gerais; Brazil. *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: Hematite, archaeological pigments, backscattering Mössbauer spectroscopy, MIMOS II, Serra da Capivara. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology Detailed stratigraphic and mineralogical descriptions of samples of pigment layers from prehistoric paintings of the Serra da Capivara National Park ¡Error! No se encuentra el origen de la referencia., in the southeast Piauí state, Brazil, were first reported on basis of chemical and mineralogical data obtained by various methods, including X-ray fluorescence spectroscopy, infrared spectroscopy, X-ray diffraction and scanning electron microscopy. From those analyzes, we know that the red pigments are mainly composed of hematite (α-Fe2O3); the yellow does contain mainly goethite (α-FeOOH); the white, gypsum (CaSO4.2H2O) or kaolinite (Al2Si2O5(OH)4); the grey is a mixture of kaolinite and hematite, and the black is derived from coal burning parts of animal carcasses. In more recent works, we used the miniaturized portable 57Fe Mössbauer backscattering spectrometer MIMOS II ¡Error! No se encuentra el origen de la referencia. to perform in situ measurements in the archaeological site known as Toca do Boqueirão do Sítio da Pedra Furada (BPF) ¡Error! No se encuentra el origen de la referencia., in order to specifically examine shades of dark red (Munsell color, 10R 3/3; reddish brown ¡Error! No se encuentra el origen de la referencia.) pigments and compare their differences relatively to the light red (10R 5/8; red) part of the same painting. The hyperfine Mössbauer parameters reveal that the dark red pigment (spectrum, Figure 1) is composed of two populations of well-crystalline hematite and very likely of a small proportion of maghemite (-Fe2O3), whereas the distinctly pigments of the pale-red portion of the painting exhibit a relatively less crystalline hematite mixed with a (super)paramagnetic Fe3+ (probably, also hematite in very small particles or paramagnetic iron in the structure of silicates). The corresponding analysis of the collected red ochre (the piece that was assumed to have been used to paint the archaeological panel) has also shown hematite and, in this case, a much larger proportion of maghemite, suggesting the possibility that the preparation of the pigment might have involved heating the mineralogical clay precursor somehow mixed with charcoal to prepare the prehistoric pigments. -10 -8 -6 -4 -2 0 2 4 6 8 10 1.011 1.008 1.005 1.002 0.999 Relative Emission Doppler Velocity, v/mm s-1 Figure 2. 57Fe Mössbauer spectrum of the dark red area of the rupestrian painting. Acknowledgements: Work supported by FAPEMIG and CNPq (Brazil). Authors thank Cecília Aparecida Lima and Anna Carolina Ferreira Borges, undergraduate students at UFPI, for their help on the field works. JDF is indebted to CAPES (Brazil) for granting the Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. References M.C.S.M. Lage, Étude archéométrique de I'art rupestre du sud-est du Piauí – Brésil. Université de Paris I, Panthéon – Sorbonne (1990) PhD thesis. 407p. G. Klingelhöfer et. al., Journal Geophysical Research 108 (E12) (2003) 8067-8084. N. Guidon and G. Delibrias, Nature V. 321 (1986) 769-771.
T03 IRON‐CONTAINING PIGMENT FROM A RUPESTRIAN PAINTING OF THE 55 PLANALTO TRADITION IN MINAS GERAIS, BRAZIL D. L. Floresta1,4, M. Fagundes2, J. D. Fabris2,3 and J. D. Ardisson4 1Instituto Federal Minas Gerais (IFMG), campus Santa Luzia, Santa Luzia, Minas Gerais, Brazil 2Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, Brazil 3Departamento de Química-ICEx, UFMG. Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil. 4Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, Minas Gerais, Brazil *Corresponding author: e-mail: denise.floresta@ifmg.edu.br Keywords: rock art, archaeometry, iron oxides Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology Archaeological rupestrian arts are of relatively spread occurrence all over the land area of the state of Minas Gerais (MG), Brazil. The archaeological Planalto Tradition is characterized by monochromic figures, especially in red or orange color, representing zoomorphic figures, particularly of cervids1,2. A fragment of a rock wall containing an archaeological painting identified as being of the Planalto Tradition was found at the site known as Itanguá, in the municipality of Senador Modestino Gonçalves (17o 49’ 41.51’’ S 43o 12’ 48.39’’ W), MG. The rock piece was collected by researchers of the Laboratory of the Archaeology and Landscape Studies of the Federal University of Valleys of Jequitinhonha and Mucuri, in Diamantina, also in MG. The painting itself is predominantly red, dark or even orange in color, but no defined shape could be clearly identified. A small subsample was cut out from the sampled rock-fragment and analyzed by conversion electron Mössbauer spectroscopy (CEMS) at room temperature (298 K). The obtained spectrum and corresponding fitted parameters are in Fig. 1 and Table 1, respectively. Results reveal that hematite (Fe2O3) is the magnetically ordered iron oxide. A (super)paramagnetic ferric component with relative spectral area RA = 64 % also appears in the Mössbauer pattern3. Figure 1- Spectrum Mössbauer and first adjust of CEMS analyses of a rock painting fragment, at room temperature. Table 1- 298 K-Mössbauer hyperfine parameters from the CEMS analysis of pigments of an archaeological rock-painting fragment.  = isomer shift relative to the Fe;  = quadrupole splitting;  = quadrupole shift; Bhf = hyperfine Field and RA = relative subspectral area. Site  ,  Bhf RA mm/s mm/s tesla % Fe2O3 0.31 -0.28 51.5 36 Fe3+ 0.40 0.67 64 The quantitative chemical analysis of the pigment on this rock fragment was made by X-ray fluorescence. The chemical composition is rather comparable for both dark red and orange pigments: the dusky region of the painting area was found to contain only ˜5 mass% more of iron than the orange area. Results from further analyses, which are currently being made, including Mössbauer measurements at low temperatures to check for the supeperamagnetic behavior, but also with grazing incidence X-ray diffraction (GIXRD) and scanning electron microscope (SEM), will be presented. References [1] V.L. Salvio (2007) MS thesis, UFMG, Brazil. 119 p. [2] R.L.S Aguiar, K.M. Lima and L. G. Freitas. Diálogos (Maringá Online) v. 16 (2012) 1026. [3] A. Kuno, M. Matsuo, A. Pascual Soto, and K. Tsukamoto. Hyp. Interact. V. 156/157 (2004) 431. Acknowledgments Work financially supported by CNPq and FAPEMIG. CAPES (Brazil) grants the visiting professorship to JDF, under the PVNS program, at UFVJM. This ongoing study is part of the PhD thesis by DLF at CDTN; her work is formally and institutionally supported by the IFMG.
T03 KINETICS OF METEORITIC Fe50Ni50 SUPERSTRUCTURE ORDER‐DISORDER 300°C 400 °C 450 °C 475 °C 500 °C 550 °C 600 °C 1 10 100 1000 10000 100000 1000000 Cumulative annealing time (min) 56 PROCESS E. Dos Santos, J. Gattacceca, P. Rochette and R. B. Scorzelli 1Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Rio de Janeiro, 22290-180, Brazil. 2Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement, UM34, CNRS/Aix-Marseille University, 1345 Aix-en-Provence, France. *Corresponding author: e-mail: edisanfi@cbpf.br Keywords: Tetrataenite, Meteorite, Apparent Curie temperature Topic: T03 – Applications in Soils, Mineralogy, Geology, Cements and Archaeology Tetrataenite is a chemically ordered L10-type Fe50Ni50 alloy detected for the first time by 57Fe Mössbauer studies in iron meteorites [1]. Because tetrataenite has very high coercivity compared to other FeNi metallic minerals found in meteorites, its presence is a proxy to the thermal history of meteorites [2]. In particular, it is a sensitive tracer of transient secondary thermal events, like those associated with impacts, that leads to disordering of tetrataenite into taenite. However, in the absence of data about the time-temperature conditions necessary to disorder tetrataenite, it is currently impossible to interpret quantitatively such observations. Several works show that thermomagnetic curves for tetrataenite are essentially flat in a temperature range below 500 °C, and drop sharply at ~ 550 °C (the apparent Curie point), although no information was provided about the heating rate [3]. At the apparent Curie point disordering takes place and tetrataenite is transformed into taenite. Thus, in order to gain insights related to the disordering kinetics of tetrataenite, we present results concerning time-temperature experiments for tetrataenite disordering, using Santa Catharina meteorite as a starting material, and magnetic properties as a proxy to the ordered state. Santa Catharina meteorite is known to contain about 50% tetrataenite [4]. Samples of about 5 mg were annealed in air, at temperatures in the 300 to 600 °C range. Annealing was carried out in several cycles ranging from 3 min to more than 10 days, followed by cooling to room temperature. Before and after each annealing step hysteresis properties were measured. At annealing temperatures below the chemical order-disorder transition temperature (~ 320 °C, [5]), no changes in magnetic properties were observed. Indeed, our results show that coercivity of remanence (BCR) remains constant after annealing experiments at 300 °C for over 6 days, indicating that magnetocrystalline anisotropy responsible for the high coercivity of tetrataenite is stable. Nevertheless, ~30 days are necessary at 400 °C to decrease BCR by about 50%, whereas annealing at 550 °C and 600 °C for ~ 10 min and ~ 3 min, respectively, decreases BCR by more than 90%, as shown in Fig. (1). 450 400 350 300 250 200 150 100 50 0 BCR (mT) Figure 1. Coercivity of remanence (BCR) vs annealing time for Santa Catharina meteorite. This data set allows to propose a quantitative time-temperature scenario to account for the disordering of tetrataenite in some meteorites. It was shown that tetrataenite disordering may take place at any temperature above the order-disorder transition for L10 superstructure phase when the appropriate time-scale is considered. Therefore the apparent Curie point for tetrataenite is not an absolute property in the sense that any estimate of this parameter should be referred to a given time-scale. Thus, we argue that the apparent Curie point estimated in previous works does not give a complete picture of tetrataenite disordering. References [1] J. F. Petersen, M. Aydin and J. M. Knudsen. Phys. Lett. V. 62 (3) (1977) 192. [2] J. Gattacceca, C. Suavet, P. Rochette, B. P. Weiss, M. Winklhofer, M. Uehara and J. M. Friedrich. Met. Planet. Sci. V. 49 (4) (2014) 652. [3] T. Nagata, J. A. Danon and M. Funaki. Mem. Natl. Inst. Polar Res., Spec. Issue V. 46 (1987) 263. [4] J. Danon, R. B. Scorzelli, I. Souza Azevedo, J. Laugier and A. Chamberod. Nature V. 284 (1980) 537. [5] J. Pauleve, D. Dautreppe, J. Laugier and L. Néel. J. Phys. Radium V. 23 (10) (1962) 841.
T03 MÖSSBAUER AND RAMAN SPECTROSCOPY OF CONCRETES USED IN THE 40 38 36 34 32 30 28 26 24 22 20 18 16 14 Dose (KGy) Ca4Al2Fe2O10 CON APASCO < 15mm CON CRUZ AZUL CON IMPER Ca3A lO6 The highest compression strength was obtained in the concrete specimen prepared with EXTRA CEMEX irradiated at 10000 kGy. Tricalcium aluminate (C3A) and tetracalcium alumnoferrite (C4AF) are main phases in cements (Fig. 2b). Iron in C4AF is bivalent (Fe2+) and trivalent (Fe3+) with the latter being in tetrahedral (T) and octahedral (O) coordinations [3]. Iron in our cements (see figure. 1a) are in trivalente state (Fe3+), distributed in two tetrahedral positions (T1) and (T2), the Fe2+ is part of the raw material (grave). EXTRA 57 CONDITINING SPENT RADIOACTIVE SOURCE F. Monroy Guzman1, M. González Neri1, 2, R. C. González Díaz1, G. Ortíz Arcivar1, I. J. Corona Pérez1, N. Nava, A.Cabral-Prieto1, L. Escobar1 1 Instituto Nacional de Investigaciones Nucleares. Carretera México-Toluca s/n, La Marquesa, Ocoyoacac, Edo. de México, C. P. 52750, México 2 Universidad Mexiquense del Bicentenario Unidad Lerma, Parque Industrial Automotriz Ex Hacienda Doña Rosa, Lerma Edo. México *Corresponding author: e-mail: fabiola.monroy@inin.gob.mx Keywords: concrete, Rama, radioactive sources Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archeology Around 8189 spent sealed radioactive sources (Am-241, Ir-192, Ra-226, Cs-137, Co-60, Sr-90, Po-210, Th-230, etc.), generated in Mexico, have been immobilized in concrete at ININ. The concretes used in the immobilization of these sources have not yet been standardized and characterized, however they must to comply with NOM-0019-NUCL-1995 [1,2]. Therefore, concrete specimens were prepared from four types of Portland cements: CPC 30RS EXTRA CEMEX, CPC 30R IMPER CEMEX, CPC 30RS APASCO, and CPC 30R CRUZ AZUL (manufactured in Mexico), using three particle sizes of the coarse aggregate (grave) (> 30 mm, 30-15 mm and <15mm). Concrete specimens were subjected to compression strength, -ray irradiation and thermal resistance assays; and characterized by using Mössbauer and Raman Spectroscopy, in order to correlate the effects of irradiation doses, thermal treatments, and compressive strengths with the oxidation states of iron. The compressive strengths of all concrete test specimens were between 30 and 50 times higher than the required by the NOM- 0019-NUCL-1995, (> 0.35 MPa) as shown in figure 1. Figure 1. Compression strenght of concrete test specimens as a function of radiation dose and thermal treatment and Raman Spectra IMPER CRUZ APASCO APASCO >30 APASCO <15 CONCRETES 12 COMPRESSION STRENGTH (Mpa) 0 200 400 600 1000 10000 THERMAL 200 300 400 500 600 700 Raman shift cm-1 CON EXTRA Ca3AlO6
1.001 1.000 0.999 0.998 0.997 0.996 0.995 0.994 EXTRA CEMEX CEMENT CONCRETE EXTRA CEMEX CONCRETE EXTRA CEMEX 200 kGy CONCRETE EXTRA CEMEX 400 kGy (a) (b) 1.000 0.995 Figure 2 Mössbauer spectra of (a) cements and raw materials (grave and sand), and a (b) -ray irradiated concrete. A discussion of the -ray irradiated concrete will be given. Generally speaking there is an oxidation (red)/reduction(blue) process of the Fe2+. The octahedral sites of Fe3+ in the original cement move to tetrahedral sites when the concrete is formed. References [1] J.Jiménez Dominguez Acondicionamiento de fuentes selladas gastadas. P.DR (PATRADER)-31, ININ, México, 2009. [2] NOM-019-NUCL-1995. Diario Oficial, Secretaría de Energía, México, 14 agosto 1996. [3] V. Lilkov, O. Petrov, Y. Tzvetanova, P. Savov, Construction and Building Materials 29 (2013) 33-42. 58 -4 -3 -2 -1 0 1 2 3 4 0.990 sand grave EXTRA CEMEX IMPER CEMEX CRUZ AZUL APASCO Transmission Velocity mm/s -4 -2 0 2 4 0.993 Transmission Velocity (mm/s)
T03 MÖSSBAUER AND X‐RAY DIFFRACTION STUDY OF ARCHAEOLOGICAL 59 CERAMICS FROM SÃO LUIZ DO MARANHÃO P. Munayco, E. Dos Santos, R.B. Scorzelli, R.A. Ikeoka and C.R. Appoloni 1Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150 - Urca, CEP: 22290-180, Rio de Janeiro, RJ – Brazil. 2 Instituto de Física, Universidade Federal de Mato Grosso, Av. Fernando Corrêa Costa, 2367, Cuiabá, Mato Grosso, Brazil. 3 Departamento de Física/CCE, Universidade Estadual de Londrina; Cx.Postal 6001,CEP 86051-990 Londrina/PR – Brazil. *Corresponding author: e-mail: mpablo@cbpf.br Keywords: Archaeological ceramics, Firing temperature, Mössbauer, XRD Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The study of cultural heritage of ancient people is essential in building the memory of any society. This knowledge may be acquired by archaeological research. Among such cultural material, ceramics are highlighted as objects of highly archeological value because they are extremely resistant to weather and environment conditions. The chemical characterization of such fragments may provide important information about the origin of the raw material, the manufacture process, the quality of the coating, indexes of the occurrence of paintings, etc., This work deals with ceramic fragments from the Sambaquis of “Panaquatira” and “Rabo de Porco” located in the São Luiz city area, Brazilian northeast. Ancient civilizations that inhabited that territory were characterized as fishing, catchers, hunters and ceramists populations. Dates obtained by termoluminescence ranged from 5730 to 127 BP. The ceramic fragments were analyzed by 57Fe Mössbauer spectroscopy and X-ray diffraction. The Mössbauer spectra of the samples from Panaquatira and Rabo de Porco were performed at room temperature, and, in a few selected cases, at low temperature in order to distinguish between paramagnetic phases and phases that are superparamagnetic at RT. The 57Fe Mössbauer spectra, from outer and inner portions of ceramic, evidenced the presence of one quadrupole doublet associated with the presence of Fe3+ species and one magnetic component associated with hematite. The inner portions show additionally one doublet associated to Fe2+ species. These results suggest that different atmospheres prevailed during the firing of the studied samples [1]. The quadrupole splitting (QS) of the paramagnetic Fe3+ component at room temperature obtained for the archaeological fragments, is used to determine its firing temperature by comparing it with clays, collected near the archaeological sites, fired in different temperatures, in the laboratory. The QS of the Fe3+ species measured at RT after refiring specimens of the archaeological pottery in air at increasing temperatures are compared with data obtained after firing clay under the same conditions. The QS for Fe3+ species in the refiring curve meets the firing curve of the clay at about 800 - 900 oC [2]. The XRD diffractograms of fragments from Panaquatira exhibit quartz, feldspars and layer silicates. Samples from Rabo de Porco show additionally mica and amphiboles suggesting a manufacturing process different from that employed in Panaquatira samples. References [1] P. Munayco, R.B Scorzelli, Hyperfine Interact. V. 222 (2013) S69. [2] C.R. Appoloni, R.A Ikeoka, O.H. Marcori, F. Lopes, M. A Rizzutto, J. F. Curado, R. B. Scorzelli, P. Munayco and A. M. Bandeira. International Symposium on Archaeometry (ISA), Los Angeles (2014).
T03 PROPERTIES MINERALOGICAL, STRUCTURAL AND ELECTRONIC PROPERTIES OF SOIL SAMPLES DISORIENTED CULTIVATED WITH SUGAR CANE USING ANALYSIS: PHYSICAL‐CHEMICAL, X‐RAY DIFFRACTION (XRD) AND MÖSSBAUER SPECTROMETRY (MS) 1.00 0.95 0.90 60 F. M. Vargas Fontalvo, H. Bustos Rodríguez, D. Oyola Lozano, Y.A. Rojas Martínez, E.A. Ávila Pedraza and G.A. Pérez Alcázar 1Universidad del Tolima. Grupo Ciencia de Materiales y Tecnología en Plasma, A.A.546, Ibagué, Colombia. 2) Universidad del Valle. Grupo Metalurgia Física y Teoría de las Transiciones de Fase, A.A.25360, Cali, Colombia * fmvargasf@ut.edu.co Keywords: Mössbauer spectrometry, agricultural soils, XRD. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The Mössbauer spectrometry (EM) of the 57Fe have been going on for several years now and has gained in importance as the information provided, in many cases, is not obtained by other techniques, in the last few decades numerous studies of soils [ 1-13] and in other fields has been implemented the combination of the Mössbauer spectrometry (EM) and X-ray diffraction (XRD) getting fruitful results) [ 14]. Sugar cane is the agricultural product of greater importance in the Valle del Cauca, Colombia, because of its impact socio-cultural and economic in the entire region, and will therefore take importance the study of the structural and electronic properties, samples of cultivated soils with sugar cane in that region, were applied multiple techniques aimed at the detection of phases present, calculations of hyperfine constants and structural properties, visualization and quantification of phases present with content, mainly of Fe+2 and Fe+3. We present a study of the mineralogy of disoriented samples of agricultural soils of different areas where sugar cane is grown in the department of Valle, using techniques of physical and chemical analysis of soils, XRD and MS. The physico-chemical characteristics of the soil, show the degree of alkalinity and texture through the measurement of chemical parameters such as pH, the percentage of organic matter and elements such as P, Ca, Mg, Na, K, Fe, Cu, Zn, Mn, B and S. also introducing the percentages of sand, silt and clay that characterize the parameters of texture. The Mössbauer spectrometry (MS) of Fe57 is being posted for several years to the study of soils and has gained importance as the information provided, in many cases, is not obtained by other techniques. Particularly the Mössbauer spectra of the samples analyzed soils of sugar cane crops show, at room temperature, the presence of mineral phases with content of Fe+2 and Fe+3. Using programs of refinement MOSFIT [16] we got the respective hyperfine parameters and comparing with Mössbauer Handbook [ 17], we identified phases as goethite, illite, kaolinite, montmorillonite and pyrite. Using XRD, mineral phases were identified with content of iron (Fe) as illite, biotite, and nontronite ferriphologopite and also the presence of other phases without content of iron (Fe) as quartz and andesine. Figure 1. illustrates the Mössbauer spectra at room temperature for two (2) soil samples sugar bowl del Valle del Cauca, Colombia, paramagnetic doublets are observed in all the spectra, which indicates mineral phases with the presence of the mineral of iron (Fe) belonging to Fe+2 and Fe+3. The parameters of the electronic content of phases with iron (Fe), such as the diversion isomeric, cleavage and field cuadrupolar hyperfine were found using the Mössbauer spectrometry Table. (2). 1.00 0.98 0.96 Sample FR57 Exp Total Fe+2 Fe+3 Fe+3 -9 -6 -3 0 3 6 9 Today's date is 09/08/14 The Document name is: ".opj, importp" relative transmission V [mm/s] (a) Exp Total Fe+2 Fe+3 Fe+3 Sample FR47 -9 -6 -3 0 3 6 9 Today's date is 09/08/14 The Document name is: ".opj, importp" relative transmission V [mm/s] (b) Figure 1. Setting Mössbauer spectra Agricultural soils cultivated with sugar cane in the department of Valle del Cauca and northern Cauca. In the analysis of the minerals from the soil samples of the cultivation of sugar cane by Mössbauer spectrometry mineral phases are determined with the presence of the mineral of iron (Fe) belonging to Fe+2 and Fe+3. We reaffirm that (MS) is a complementary tool and valid for the analysis of electronic properties of mineral samples of agricultural soils. References [1] Humberto Bustos Rodríguez, Dagoberto Oyola Lozano, Yebrayl A. Rojas Martínez, Marlene Rivera Pinilla and Germán A. Pérez Alcázar. Characterization of mineral phases of agricultural soil samples of Colombian coffee using Mössbauer spectroscopy and X-ray diffraction. Hyperfine Interact (2012) 208:13-18.
[2] S.P. Tanejaa and D. Rajb. Mössbauer and X-ray studies of soils. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. Volume 76, Issues 1-4, 4 April 1993, Pages 233-235. [3] Cerón Loayza, María Luisa. Estudio mineralógico de suelos agrícolas por espectroscopia Mössbauer. Tesis de Maestría. UNBA. 2001. [4] Ana E. Mijovilovich. Estudio Mössbauer de óxidos e hidróxidos de Fe: Aplicación al estudio de suelos. Tesis Doctoral. UNBA. 1997. [5] A. E. Mijovilovich, H. Morras, H. Causevic, C. Sarago-vi, Hyp. Int., 122. 199, pp. 83-85. [6] H.P. Gunnlaugsson, H. Rasmussen, M.B. Madsen, P. Nørnberg. New analysis of the Mössbauer spectra of olivine basalt rocks from Gusev crater on Mars. Planetary and Space Science 57 (2009) 640–645. [7] Claudia Hidalgo, Jorge D. Etchevers, Antonio Martínez-Richa, Hernani Yee-Madeira, Héctor A. Calderon, Ricardo Vera-Graziano, Francisco Matus. Mineralogical characterization of the fine fraction (b2 μm) of degraded volcanic soils and tepetates in Mexico. Applied Clay Science (2009). [8] Luke J. Kirwan, Francis A. Deeney, Gerard M. Croke, Kieran Hodnett. Characterization of various Jamaican bauxite ores by quantitative Rietveld X-ray powder diffraction and 57Fe Mössbauer spectroscopy. Int. J. Miner. Process. 91 (2009) 14–18. [9] Bustos Rodríguez Humberto. Estudio de propiedades electrónicas y estructurales de muestras minerales de menas auríferas colombianas, mediante el uso de microscopia óptica, espectrometría Mossbauer, difracción de rayos-x, SIMS y LAM-ICP-MS. Ph. D. Physical Sciences Tesis. Universidad del Valle (2006). [10] H. Bustos Rodríguez, Y. Rojas Martínez, D. Oyola Lozano, G.A. Pérez Alcázar, M. Fajardo, J. Mojica and J. C. Molano. Hyp. Int. (2005)161:61-68. [11] H. Bustos Rodríguez, D. Oyola Lozano, Y. A. Rojas Martínez, G.A. Pérez Alcázar A. G. Balogh. Invisible gold in Colombian auriferous soils. Hyp. Int. (2005) 166:605–611. [12] Humberto Bustos Rodríguez, Dagoberto Oyola Lozano, Yebrayl A. Rojas Martínez, Germán A. Pérez Alcázar, Stefan Flege, Adam G. Balogh, Louis J. Cabri, Michael Tubrett. Mineralogical analysis of auriferous ores from the El Diamante mine, Colombia. Hyp. Int. (2007) 175:195-206. [13] J. J. Ipus, J. Mojica* y G.A. Pérez Alcázar. Caracterización de arcillas colombianas por espectroscopia Mössbauer y difracción de rayos-x. Revista Colombiana de Física, Vol. 37, No. 1, 2005. [14] Mössbauer and EPR spectra for glasses and glass-ceramics prepared from simulated compositions of Lunar and Martian soils [15]Instituto Colombiano Agropecuario - ICA, Fertilizantes en diversos cultivos, Centro Experimental Tibaitata, octubre 1981. [16] F. Varret, J. Teillet, Unpublished MOSFIT program (1976). [17] J.G Stevens, A.M. Khasanov, J.W. Miller, H. Pollak, Z. Li. Mössbauer Mineral Handbook. Mössbauer Effect Data Center (2002). 61
T03 REVISITING THE TOLUCA METEORITE R. B. Scorzelli, E. dos Santos 62 and P. Munayco 1Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Rio de Janeiro, 22290-180, Brazil. 2Instituto de Física, Universidade Federal de Mato Grosso, Av. Fernando Corrêa Costa, 2367, Cuiabá, Mato Grosso, Brazil. *Corresponding author: e-mail: scorza@cbpf.br Keywords: Toluca meteorite, Mössbauer, Octahedrites Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The important TOLUCA shower comprises many thousands of fragments which have been recovered from a rather small area on the hillsides around the village of Xiquipilco, situated in a remote branch of the Toluca Valley network some 25 km north-northeast of Toluca, Mexico. The cumulative weight of all speciemns in registered collections is about 2,100 kg, but it is quite certain that much more material, that can be estimated in ~ 3 tons, has been found and distributed. For centuries the natives of Xiquipilco searched for the iron fragments after each new rainstorm, and they used this iron for the forging of their agricultural implements and iron tools (spades and axes). Toluca first came to be known as a meteorite locality in 1784 which is the year accepted for the first report on the Toluca shower. This 3 ton mass meteorite, is an iron meteorite, classified as a coarse octahedrite, chemical type IAB and when etched, exibit beautiful interwoven Widmansttäten patterns. Iron meteorites, composed of iron-nickel alloys, have played an important role in the study of the iron-nickel phase diagram, due to the fact that they have cooled with a rate of about 1º C/106 years. The Toluca octahedrite, as most of the meteorites belonging to this group, is composed mainly of two Fe-Ni phases, kamacite, bcc structure (- phase) and taenite, fcc structure (-phase). The two phases have definite crystallographic orientations relative to each other forming the so called Widmanstätten pattern (Fig.1). Generally this pattern continues with unchanged orientations throughout the meteorite showing that the meteorite originally, in the high temperature state, was a single crystal with fcc structure. By the very slow cooling process plates of kamacite precipitated along the {111} planes of the fcc crystal, and by growth of the kamacite plates the meteorite finally consists of alternating – and intersecting – plates of kamacite and taenite parallel to the {111} planes of the original fcc crystal. This Widmanstätten pattern is unique for the iron meteorites called octahedrites, basically due to their slow cooling. Figure 1. Widmanstätten pattern Plates of taenite, extracted from bulk material of the Toluca meteorite by selective dissolution of the kamacite in diluted acid, have played an important role in the pioneer study of the Fe50Ni50 ordered phase, tetrataenite. These plates allowed the discovery of tetrataenite using 57Fe Mössbauer spectroscopy (57Fe-MS) [1]. Soon after, also by 57Fe-MS, tetrataenite was detected in the Santa Catharina iron meteorite and in metal particles of chondrites, always associated to a singlet [2]. This phase is the natural analog of synthetic ordered FeNi which has been produced by neutron irradiation of Fe50Ni50 alloys [3]. Rancourt and Scorzelli [4] proposed that the singlet is an antiferromagnetic low-spin -phase (called antitaenite) occurring as an intergrowth with tetrataenite, indicative of an equilibrium state at low temperature in the Fe-Ni system at 25 – 30 at% Ni. Since both phases have the same lattice parameters it is difficult to detect antitaenite with classical XRD. It was only using XRD with synchrotron radiation that the presence of this phase was confirmed for the first time in the Toluca and other iron meteorites, by diffraction methods [5]. References [1] Petersen J. F., Aydin M. and Knudsen J. M. 1977. Phys. Lett. V.62(3)192(1977). [2] Danon J., Scorzelli R. B., Souza Azevedo I. and Michel-Levy M. C. 1979. Nature V.281(1979) 469. [3] Paulevé J., Dautreppe D., Laugier J. and Néel L. 1962. J. Phys. Radium V.23(1962)841. [4] Rancourt D. G. and Scorzelli R. B. J. Magn. Magn. Mater. V.150 (1995) 30. [5] Scorzelli, R. B., Avillez, R. R., Duttine, M. and Munayco, P. Activity Report (LNLS) V.1(2007)1.
T03 STRUCTURAL AND ELECTRONIC PROPERTIES OF DISORIENTED SOIL SAMPLES 63 OF CRAFTS CLAY IN TOLIMA, COLOMBIA J.U. González Arias, H. Bustos Rodríguez, F. M. Vargas Fontalvo, D. Oyola Lozano, Y.A. Rojas Martínez, E.A. Ávila Pedraza y G.A. Pérez Alcázar 1Universidad del Tolima. Grupo Ciencia de Materiales y Tecnología en Plasma, A.A.546, Ibagué, Colombia. 2 Universidad del Valle. Grupo Metalurgia Física y Teoría de las Transiciones de Fase, A.A.25360, Cali, Colombia. * mg.ugonzalez@gmail.com Keywords: Mössbauer spectrometry, soils, XRD. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology A study of the mineralogy of clay soils disoriented samples that are used for handicrafts in Guamo-Tolima, using techniques Physicochemical Analyses of soils, X-ray diffraction (XRD) spectrometry Mössbauer (MS), techniques that have been implemented in numerous studies with good results [1-3]. Using Mössbauer spectroscopy (MS) of Fe57 measure parameters such as the deviation hyperfine isomeric (IS), the quadrupole splitting (QS) and the hyperfine field (HF). Particularly the samples of clayey soils at ambient temperature show the presence of mineral phases containing Fe+2 and Fe+3. Also obtained spectra show sextet that identifies the presence of magnetic phases. Also, occurs in other samples doublets characterizing paramagnetic phases. Using refinement programs the respective hyperfine parameters obtained and compared with Mössbauer Mineral Handbook, phases identified as illite, biotite and baumita. Using XRD, identified mineral phases containing iron as baumita (Mg, Mn, Fe, Zn) and also the presence of other phases without iron content as silica (SiO2), montmorillonite [Na0.3 (Al, Mg)2 Si, kaolinite [Al2Si2O5(OH) 4] and Moscow [0.33 (NH4) 2OAl. Clay soils of Chamba Tolima are used to produce one of the best crafts of Colombia globally recognized also by their physical characteristics such as high surface area, cation exchange capacity, absorbency, hydration and swelling, plasticity, thixotropy it has enabled man to give various uses and abundant presence in our environment hence the importance of their study. Our case is an industry that benefits family businesses who applied tradition engaged in this activity from generation to generation, where craftsmanship occurs in fireclay which is recognized nationally and internationally for its beauty and quality. Samples of clay soil of Chamba Tolima, Colombia, were analyzed by different techniques such as physic-chemical analysis, XRD, MS, which allowed us to detect the presence of different mineral phases as calculate hyperfine and structural properties also display phases present containing mainly Fe and Fe+2 y Fe+ 3, (a) (b) Figure 1 Mössbauer spectra adjustment. disoriented samples of clay soils. AC344 sample (a) and shows AC345 (b). The diffractograms were refined using the method Rietvel. The electronic parameters of the phases containing iron (Fe), the isomer shift, splitting quadrupole and hyperfine field were found using Mössbauer spectroscopy and the spectra were refined using a refinement program [4], calculated respective parameters hyperfine and confronted with Mössbauer Mineral Handbook [5]. Figure No. 1 presents the spectra obtained by Mössbauer spectrometry. Coincident with XRD results, are also Fe phases with the presence of Fe+2 and Fe+3. References [1] J. J. Ipus, J. Mojica* y G.A. Pérez Alcázar. Caracterización de arcillas colombianas por espectroscopia Mössbauer y difracción de rayos-x. Revista Colombiana de Física, Vol. 37, No. 1, 2005. [2] Cerón Loayza, María Luisa. Estudio mineralógico de suelos agrícolas por espectroscopia Mössbauer. Tesis de Maestría. UNBA. 2001. [3] STEVENS, J.G., KHASANOV, A.M., MILLER, J.W., POLLAC, H. Y LI, Z.(1998): Mössbauer Mineral Handbook. Mössbauer Effect Data Center, North Carolina 1998. [4] Varret, F. & Teillet, J. (1976). Unpublished MOSFIT program. [5] STEVENS, J.G., KHASANOV, A.M., MILLER, J.W., POLLAC, H. Y LI, Z. (1998): Mössbauer Mineral Handbook. Mössbauer Effect Data Center, North Carolina 1998.
T04 ABUNDANCE AND STATE OF IRON IN VITAMIN SUPPLEMENTS P.I. Arredondo S., C.A. 64 Barrero, K.E. Garcia and J.M. Greneche 1Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia. 2LUNAM, Université du Maine, Institute des Molécules et Matériaux du Mans, IMMM UMR CNRS 6283, Université du Maine 72085 Le Mans Cedex France. *E-mail: patriciaines@gmail.com Keywords: Mössbauer effect, vitamin supplements, sulfate, fumarate, iron state. Topic: T04- Biological and Medical Applications The general forms of iron in vitamin supplements are fumarate or sulfate. It is important for manufacturer as well as for consumer, to know the iron content and its state in these vitamins. The Mössbauer effect is a tool that has been used for that purpose[1]. However, to the best of our knowledge, the relative recoilless f-fractions for these samples have not been yet determined. In this work, the room temperature (RT) relative recoilless f-factors of six purchased commercial vitamins with respect to α-Fe powder were calculated by applying a method of the two relative sub-spectral areas in a mixture of known amounts of the compound and a standard sample [2]. The procedure was repeated three times for different amounts of the compounds and reference. The obtained spectra were thickness-corrected and fitted using commercial software [3]. Figure 1 shows a typical thickness-corrected spectrum of a mixture of Ferro-F-800 and of α-Fe powder, which was fitted with a quadrupolar doublet and a sextet. The spectra for the other samples were similar. The derived hyperfine parameters and the relative f-factors are presented in Table 1. From these parameters, it can be inferred that the states of the irons were Fe2+ in all vitamins, in good agreement with other reports [1]. The relative recoilless f-fractions for the vitamins with respect to α-Fe are also presented. In the case of Laproff vitamin, the amount of iron content was not specified by the manufacturer. However, by using the relative recoilless f-fractions of IRON and Ferro-F-800, which are also vitamins based on iron-sulfates, the amount of iron-sulfate in Laproff was estimated at between 41 and 49 % per tablet; anything else would be excipients. -8 -4 0 4 8 1.00 0.98 0.96 0.94 Relative transmission (a.u.) Velocity (mm/s) Figure 1. RT Mössbauer spectrum of a mixture of Ferro-F-800 and of α-Fe powder. Table 1: RT hyperfine parameters and relative recoilless fractions for some vitamin supplements. Estimated errors are of about 0.01 mm/s for isomer shift , and for quadrupole splitting Δ; and 2% for relative sub-spectral areas. Sample  (mm/s) Δ (mm/s) As /AαFe s/αFe Ferro-F-800 1.25 2.70 19/81 1.10±0.02 Laproff 1.27 2.74 27/73 - IRON 1.28 2.71 12/88 0.91±0.09 Mitrum vitTM 1.16 2.18 3/97 0.66±0.03 Prenavit 1.21 2.25 10/90 1.06±0.06 IOFI 1.21 2.26 23/77 0.86±0.03 References [1] M.I. Oshtrakh, O.B. Milder, V.A. Semionkin. J. Pharm. Biomed. Anal. 40 (2006) 1281–1287. [2] Oh, Sei J., and D. C. Cook. J. Appl. Phys. 85 (1999): 329-332. [3] K. Lagarec and D.G. Rancourt, Recoil: Mössbauer Spectral Analysis Software for Windows, version 1.0 (Department of Physics, University of Ottawa, Canada, 1998).
T05 EFFECT OF TITANIA ON THE CHARACTERISTICS OF A TIN‐PLATINUM CATALYST P. Morales-Gil1, N. Nava1 65 and E. Baggio-Saitovitch2 1Instituto Mexicano del Petróleo, Eje Lázaro Cárdenas 152, México D.F. 07730 2) Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, CEP 22290-180, Rio de Janeiro, Brasil *Corresponding author: e-mail: moralesp@imp.mx Keywords: Mossbauer spectroscopy, Pt-Sn Catalyst, dehydrogenation. Topic: T05- Catalysis, Corrosion and Environment Pt-Sn bimetallic catalysts dispersed on alumina are commonly used for reforming and dehydrogenation reactions (1-5). In this research work, Pt and Sn were supported on titania. The resulting interactions between the components in the prepared samples, before and after treatment with hydrogen, were studied by Mossbauer spectroscopy, X-ray diffraction and Rietveld refinement. The results show the presence of Pt and SnO2 after calcinations. After the reduction process, PtSn, and Pt3Sn alloys were identified. The Rietveld refinement analysis shows that some Ti4+ atoms were replaced by Sn4+ atoms in the titania structure. Finally, the Mossbauer spectroscopy and X-ray diffraction results indicate that metallic platinum and SnO2 are encapsulated by a TiOx layer. References [1] L. C. de Menorval, A. Chaqroune, B. Coq and F. Figueras, Journal Chemical Society, Faraday Trans 93 (20) (1997) 3715. [2] L. D. Sharma, M. Kumar, A. K. Saxena, D. S. Rawat, T. S. Prasada Rao, Applied Catalysis A: General 168 (1998) 251. [3] R. D. Cortright, J. M. Hill, J. A. Dumesic, Catalysis Today 55 (2000) 213. [4] T. Inoue, K. Tomishige, Y. Iwasawa, Journal Chemical Society, Faraday Trans 92 (3) (1996) 461. [5] A. Borgna, S. M. Stagg, D. E. Resasco, Journal Physical Chemisty B 102 (1998) 5077.
T05 HEMATITE SYNTHESIS FROM FERRIHYDRITE TRANSFORMATION: STUDY OF 66 CONVERSION RATE REACTION N. Pariona, K. I. Camacho, J. Quispe-Marcatoma, W. T. Herrera, A. I. Martinez, E. Baggio-Saitovitch 1Centro de investigación y de estudios avanzados del Instituto Politécnico Nacional unidad Saltillo, Coahuila, México. C.P. 25903. 2Facultad de ciencias físicas, Universidad Mayor de San Marcos, Lima, Perú. 3Centro Brasileiro de Pesquisas Físicas, Río de Janeiro, 22290-180, Brazil. *Corresponding author: e-mail: nicolaza.pariona@cinvestav.edu.mx Keywords: Ferrihydrite, Hematite, XRD, Mössbauer Spectroscopy, Magnetization. Topic: T05- Catalysis, Corrosion and Environment. Hematite is widely used as an efficient material for water remediation. The synthesis from ferrihydrite pathway is a practical and economical method. The hematite properties change with many parameters such as: ferrihydrite synthesis, anionic media, pH, reaction time, as well as the kind of catalyst used. The catalysts are used for increasing the reaction velocity and promote the growth of a single crystal phase. Hematite has been synthesized from the transformation of 2-lines ferrihydrite, using NaHCO3 as buffer and adding Fe(II) salts as catalyst in a molar ratio of Fe2+/Fe3+ = 0.02. Mössbauer spectroscopy and magnetometry were used to monitor different stages during the hematite synthesis. We found that hematite is formed since 30 minutes of reaction (figure 1a) and the use of NaHCO3 as buffer is essential to maintain the pH between 7-8 and avoid the formation of other phases like goethite. The XRD study shows that there is no other phase involved in the sample but the Mössbauer analyses (figure 1b) shows that until 150 minutes, residues of 2 lines ferrihydrite are present in the product. References (1) Liu, H.; Ma, M.; Qin, M.; Yang, L.; Wei, Y. J. Solid State Chem. 2010, 183, 2045–2050. (2) Liu, H.; Yang, L.; Ma, M.; Li, P.; Wei, Y. J. Solid State Chem. 2010, 183, 542–546. (3) Cudennec, Y.; Lecerf, A. J. Solid State Chem. 2006, 179, 716–722.
Figure 1. a) XRD patterns, b) Mössbauer spectrum for the samples at room temperature. 67
T05 HYBRID HETEROJUNCTIONS BASED ON α‐Fe2O3/CARBON DOTS AS HIGH 68 EFFICIENT PHOTOCALYST UNDER VISIBLE LIGHT Tiago Cabral Araújo1 Henrique dos S. Oliveira,2 José J. Sá Teles,1 Manoel J. M. Pires,1 Luiz C. A. de Oliveira,2 João P. de Mesquita 1, José D. Fabris1* 1Department of Chemistry – Federal University of Jequitinhonha and Mucuri’s valley, MGT 367, CEP 39100-000, Diamantina, MG, Brazil 2Department of Chemistry - Federal University of Minas Gerais, Av. Antônio Carlos, 6627, CEP 31270-901, Pampulha,Belo Horizonte, MG, Brazil. . *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: nanocomposite hybrid, -Fe2O3, carbon dots Topic: T05- Catalysis, Corrosion and Environment Iron oxides are promising candidates for the development of nanophotocatalysts for having good activity and chemical stability under visible radiation. Due mainly to the rapid recombination of the electron–hole pair, Fe2O3 itself usually presents a very lower photocalytical activity [1]. Carbon dots (CDots) are a new class of fluorescent carbon nanomaterials accidentally discovered, during electrophoretic purification of carbon nanotubes [2]. However, for their ability to control radioactive emissions and absorptions, CDots are promising candidates for the development of highly efficient photocatalysts destined to applications in environmental and energy technologies [3]. In this report, it is describe a work devoted to the preparation a hybrid nanophotocatalyst consisting of α-Fe2O3 and carbon nanostructures in aqueous medium, which was used in the photocatalytic degradation of the indigo-carmine dye, in a process activated with visible light (> 400 nm). Figure 1, 57Fe-Mössbauer patterns at 293.5 K: (a) Fe2O3, and (b) Fe2O3/CDots. The heterostructures were obtained with 5 % CDots. Similarly to what can be drawn from the Mössbauer spectra in Figure 1, the powder X-ray diffraction peaks (patterns not shown) are characteristic of -Fe2O3 (JCPDS card # 33-664) indicating that the synthesis of iron oxide with CDots does not significantly change its crystalline structure. The mean coherent length was determined with the Scherrer equation by taking the peak centered at ~33.3 º2, corresponding to the plane (104) The values so obtained were 36.5 and 24.6 nm for the sole -Fe2O3 and the hybrid nanocomposite, respectively. The curves of photocatalytic activity (Figure 2) evidence that the rate of degradation with the -Fe2O3/CDots under visible light (> 400 nm) is much higher, between the two materials. Figure 2. Photocatalytic activity of the materials prepared as measured through the degradation of the indigo-carmine dye.
Preliminary results suggest that the catalytic activity is promoted by CDots anchored on the surface of the oxide particles. This arrangement tends to increase the concentration of substrate molecules on the surface of the photocatalyst, thus the light-absorbing capacity, and lower rate of recombination of electron-hole pair. References [1] Li, H.; Kang, Z.; Liu, Y.; Lee, S.-T. Journal of Materials Chemistry 2012, 22, 24230. [2] Xu, X.; Ray, R.; Gu, Y.; Ploehn, H. J.; Gearheart, L.; Raker, K.; Scrivens, W. A. Journal of the American Chemical Society 2004, 126, 12736. [3] Sivula, K.; Zboril, R.; Le Formal, F.; Robert, R.; Weidenkaff, A.; Tucek, J.; Frydrych, J.; Grätzel, M. Journal of the American Chemical Society 2010, 132, 7436. 69
T05 IRON NANOSTRUCTURES SYNTHESIZED BY PULSED PLASMA IN LIQUIDS FOR 70 THE REMOVAL OF CHROMIUM IN WATER O. Olea-Mejía, A. Cabral- Prieto, U. Salcedo-Castillo, O. Olea-Cardoso and R. López-Castañares 1 Centro Conjunto de Investigación en Química Sustentable CCIQS UAEM-UNAM. Facultad de Química. Universidad Autónoma del Estado de México.Toluca, Estado de México. 2 Instituto Nacional de Investigaciones Nucleares, Departamento de Física, Apdo. Postal 18-1027, México. D. F., México. 3 Facultad de Química. Universidad Autónoma del Estado de México.Toluca, Estado de México. *Corresponding author: e-mail: oleaoscar@yahoo.com.mx Keywords: Pulsed Plasma in Liquids, Water Treatment Topic: T05- Catalysis, Corrosion and Environment Iron and iron compounds in the nanometric scale have been widely used for removal of pollutants in water. Chemical methods for the synthesis of nanoparticles yield in many cases undesired by-products and/or particles covered with different molecules. This is a problem when treating water since the nanoparticles surface is not in close contact with the pollutant to be removed. To avoid this problem several physical methods exist to create nanostructures. In this work we used the Discharge Plasma in Liquid to form iron and/or iron oxides nanostructures; this technique yield uncovered particles in solution and no chemical by products are produced other than ionic Fe species. We used a DC Power source and a commercial Soldering Iron to produce de Pulsed Plasma. Particles were characterized by TEM to study their sizes and shapes. In order to investigate about the chemical species of iron, Mossbauer Spectroscopy was performed on the different samples (Figure 1). Once the colloid is formed, orange skin is impregnated with these nanoparticles for the removal of Cr+6. The water treatment experiments were conducted in a batch system at different concentrations of nanostructures and with pure orange skin at a concentration of Cr+6 of 50 ppm. The skin can alone remove some Cr+6 from the polluted water. However, when using iron based nanostructures supported on the orange skin, the removal is much higher and the final concentration in the mother solution can reach a few ppm or even zero ppm (Table 1). Figure 1 Mossbauer spectrum (experimental and deconvolusions) of Fe produced in methanol. Table 1 Chromium removal by the orange skin – Fe composites at different experimental conditions. Refernces [1] Wilkin, R. T., Su, C., Ford, R. G., & Paul, C. J. (2005). Chromium-removal processes during groundwater remediation by a zerovalent iron permeable reactive barrier. Environmental science & technology, 39(12), 4599-4605. [2] López-Téllez, G., Barrera-Díaz, C. E., Balderas-Hernández, P., Roa-Morales, G., & Bilyeu, B. (2011). Removal of hexavalent chromium in aquatic solutions by iron nanoparticles embedded in orange peel pith. Chemical Engineering Journal, 173(2), 480-485.
T05 MAGNETIC HETEROGENEOUS CATALYST FOR THE CONVERSION OF TRIACYLGLEROLS IN THE OIL OF MACAÚBA (Acrocomia aculeata) FRUITS INTO METHYL ESTERS 71 A. L. Macedo, J. D. Fabris, M. C. Pereira, M. J. M. Pires, W. L. Oliveira, J. D. Ardisson 1DSc student in Biofuels at Federal University of the Jequitinhonha and Mucuri Valleys dos Vales Jequitinhonha e Mucuri (UFVJM), 39100-000 Diamantina, MG, Brazil 2PRPPG - UFVJM, Campus JK, 39100-000 Diamantina, MG, Brazil 3Institute of Science, Engineering and Technology, UFVJM, 39803-371 Teófilo Otoni, MG, Brazil 4Institute of Science and Technology, UFVJM, 39100-000 Diamantina, MG, Brazil 5Center for the Development of Nuclear Technology (CDTN/CNEN), 31170-130 Belo Horizonte, MG, Brazil *Corresponding author: jdfabris@gmail.com Keywords: Biofuels, iron oxide, biodiesel, transesterification, macaúba T05- Catalysis, Corrosion and Environment The intensive search for optimized chemical industrial processes to produce biofuels has been bringing about, in more recent times, scientific efforts towards the research and development of new efficient heterogeneous catalysts specifically directed to convert triacylglicerols and free fatty acids of bio-oils into their corresponding mixture of methyl (also, ethyl) esters. The resulting mixture of esters essentially forms the so known biodiesel and biokerosene fractions, which may be and, often are, blended, respectively, with the mineral diesel or kerosene, to form the alternative fuel to power internal combustion engines or airplane turbines. This report describes a work being devoted to the synthesis of nanosized magnetic iron oxide and its composite catalyst formed with KI-functionalized silica to form the heterogeneous catalyst to be used on the transesterification of triacylglicerols in the oil from the seed core of fruits of the macaúba palm (Acrocomia aculeata) into methyl esters. The magnetic iron oxide was obtained by mixing FeCl3 and FeCl2 in molar ratio of 2:1 in an aqueous alkaline medium, followed by centrifuging and lyophilizing the product after a 30 min-reaction. The individual solid components and the composite itself were first characterized for their chemical, crystallographic and 57Fe hyperfine structures by X-ray fluorescence, powder X-ray diffractometry (XRD) and Mössbauer spectroscopy. The room temperature (˜298 K) Mössbauer spectrum of the sole magnetic iron oxide nanopowder is shown in Figure 1(a). This spectrum is formed by broad resonance sextets due to the coupling of the magnetic hyperfine field with the dipolar magnetic moment at 57Fe nuclei on both Fe3+ in tetrahedral and, probably, mixed valence Fe3+/2+ in octahedral coordination of the iron oxide spinel structure, as it could be deduced from XRD data (pattern not shown). Fitting the Mössbauer spectrum with an independent model of hyperfine fields distribution may lead to confirm the putative occurrence of, even though eventually not only, superparamagnetic magnetite (Fe3O4) in some relatively broad distribution of sizes of very small particles. a) b) Figure 1. Mössbauer spectra (a) at room temperature (˜298 K) for the synthesized magnetic iron oxide and (b) at 150 K for the sample of KI-functionalized silica composite with magnetic iron oxide after being used as catalyst on the transesterification reaction. Further Mössbauer measurements, at room (˜298 K) and lower (298 K > T > 120 K) temperatures, for the magnetic composite catalyst material, before and after being used in the transesterification reaction, are currently in progress. The Mössbauer spectrum for the sample at 150 K (Figure 1(b)) after being used as catalyst indicates the occurrence mainly of maghemite (γ-Fe2O3) as magnetic iron oxide. The chemical effectiveness of this catalyst on the transesterification reaction with methyl alcohol, as evaluated by analyzing the produced methyl-esters mixture with gas chromatography coupled with mass spectrometer, was found to be indeed very promising to the production of biofuels.
Acknowledgements: Work supported by FAPEMIG and CNPq (Brazil). ALM thanks CAPES (Brazil) for sponsoring her DS studentship at UFVJM. JDF is also indebted to CAPES for granting his Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. 72
T05 MILLING OF 2‐FERRIHYDRITE AND AKAGANEITE AND ITS EFFECT ON THEIR Difractogramas superpuestos 2-Ferrihidrita 2-Ferr. Molida I 40 50 60 70 80 2 theta 73 ADSORPTION OF ARSENIC (v) K. E. García, C. Aristizabal and C. A. Barrero Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 # 52-21, Medellín, Colombia. *Corresponding author: e-mail: kgarciat05@gmail.com Keywords: Adsorption of arsenic, iron oxides, milling Topic: T05 - Catalysis, Corrosion and Environment Adsorption of arsenic (As) has been studied using a variety of adsorbents, including: phyllosilicates, silica, iron oxides and aluminum oxides. The modification of the surface of these particles plays an important role in their adsorption capabilities. The use of iron oxides has a great advantage due to their large surface areas, which allows the presence of abundant active sites for adsorption. Arsenic (V) is a toxic element which can cause serious health problems to the population exposed to it [1]. The routes of human exposure are basically air, water or food. In a previous work, pure and Al-doped akaganeites were prepared in the presence or absence of urea [2]. It was found that the maximum adsorption of As was for Al-doped -FeOOH prepared in 0.4 M urea, which was named as -Fe(Al)OOH-urea. In this work, we compare the As adsorption capabilities of un-milled and ball milled -Fe(Al)OOH-urea and 2-line ferrihydrite. The milling is performed with the purpose to modify the nanostructure of the oxides. This process was done in air at atmospheric pressure and at room temperature in a Fritsch Pulverisette 5 planetary ball mill, using agate vials of 250 ml in volume and balls of 10 mm in diameter made of the same material. The angular speed of disc was of 100 rpm, the ball to powder mass ratio was of 1:20, and the milling time was of 3 h. The room temperature Mössbauer spectra (RT-MS) of milled and un-milled -Fe(Al)OOH-urea samples were fitted with two doublets showing similar hyperfine parameters [3]. On the other hand, the RT-MS for the milled and un-milled ferrihydrites were fitted by introducing a single doublet with similar hyperfine parameters [3]. XRD (see Figure 1), FTIR and RAMAN spectroscopy also demonstrated that akaganeite and 2- line ferrihydrite are the only compounds presented in the un-milled and milled samples, and that therefore the milling did not induced transformation to other phases. The kinetics of As absorption was determined by atomic adsorption spectroscopy, and was performed by adding 0.1g of the adsorbent into a 200 ml solution containing 600 ppb of As (V) at pH 7.0 and at RT. We have found that the milling did not improve the adsorption capability of the 2-line ferrihydrite. However, the As (V) adsorption of un-milled akaganeite after 60 min of initiated the kinetic process was higher in comparison to the As adsorption of the milled sample. The As adsorption capability at 60 min followed the order: milled-ferrihydrite  un-milled-ferrihydrite  un-milled--Fe(Al)OOH-urea  milled--Fe(Al)OOH-urea. Because, the adsorption process involves the interaction of adsorbing species with surface hydroxyl and other groups of the iron oxides, it is probable that these active surface sites are modified by the milling, particularly in the case of the akaganeites. 1,0 0,8 0,6 0,4 0,2 0,0 I nt ens i dad R el at i v a Figure 1. XRD patterns of milled (green lines) and un-milled 2-Ferrihydrites (blue lines). nt ensi t y References [1] K. A. Matis, M. Lehmann, A. I. Zouboulis, P. Misaelides et al. eds, Natural Microporus Materials in Environmental Technology, Kluwer Academic Publishers, The Netherlands, 1999. pp. 463-472. [2] K. E. García, A. E. Tufo, E. E. Sileo and C. A. Barrero, Book of Abstracts of XII Latin American Conference on the Applications of the Mössbauer Effect, LACAME-2010, Lima, Peru, Nov. 2010. ISBN 978-612-4072-08-6, Abstract T05117, p. 158. [3] R.M. Cornell and U. Schwertmann. 2003. The Iron Oxides: Structure, Properties, Reactions, Ocurrences and Uses Preparation and Characterization, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
T05 SORPTION OF CHROMIUM (VI) BY Mg/Fe HYDROTALCITE TYPE COMPUNDS I. García-Sosa, A. Cabral- 74 Prieto N. Nava), M.T. Olguín, Luis Escobar, R. López- Castañares, O. Olea- Cardoso (1). Departamento de Química, Instituto Nacional de Investigaciones Nucleares, Apartado postal No. 18-1027, Col. Escandón, Del. Miguel Hidalgo, 11801, México D. F., México;, irma.garcia@inin.gob.mx, e-mail:agustin.cabral@inin.gob.mx teresa.olguin@inin.gob.mx;(2). Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas, 152, Col. San Bartolo Atepehuacan, Del. Gustavo A. Madero, C. P. 07730, México D. F.; email: tnava@imp.mx; (3). Facultad de Química, Universidad Autónoma del Edo. de México, Toluca Edo. de México, México; email: rlc@anuies.mx, olc@anuies.mx *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: Hydrotalcites, Cr(VI), environment Topic: T05- Catalysis, corrosion and environment Layered double hydroxides (LDHs), also known as hydrotalcites or anionic clays, have the general formula [M2+(1-x) M3+x (OH)2]x+[Am-x/m●nH2O], where M2+ could be Mg(II) and M3+ could be Al (III) or Fe(III), and Am- is an exchangeable anion. These compounds are mainly utilized as catalysis precursors, but they have also been used for removal of contaminants such as chromium [1, 2], among other processes. In recent years, several authors have documented the use of LDHs [1] for chromium removal from wastewater, observing that these methods are environmentally friendly. So far, a few reports have been published on the adsorptive behavior of Mg/Fe LDHs for the removal of chromium [2]. These types of compounds are mainly synthesized by co-precipitation [2]. In this work the synthesis products of Mg/Fe LDH compounds poorly, HTFeMO9A, and well crystallized, HTFeMO9A, samples were studied. Batch system was used to determine the sorption isotherms with 100 mg of any of these samples which were put in contact with 10 mL of different concentrations of potassium dichromate (K2Cr2O7) (from 5 to 100 mg K2Cr2O7/L at pH values of 3 and 5. The adsorbed average quantity of K2Cr2O7 per gram of LDH was around 6.3 mg/g. This value is twice higher than the one reported by Das [2] for Mg/Fe LDH compound without any calcination. Ferrihydrite in both LDH samples was always detected from Mössbauer and Raman spectroscopies, Figs. 1 and 2, respectively. A discussion of its presence in the sorption of K2Cr2O7 is made. Raman spectra are characteristic of LDHs having a ratio of Fe3+/(Mg2+ + Fe3+)  0.5, the presence of ferrihydrite makes, however, ambiguous this conclusion. On the other hand, the presence of the chromate anions after the sorption process are easily detected from these Raman spectra, an aspect that is important for this study. Conclusions. The prepared Mg2+/Fe3+ LDHs result to be viable for the adsorption of contaminants. The role of ferrihydrite in this sorption process must be further studied to understand the sorptive properties of these compounds
Figure 1 shows the Mössbauer spectrum of HTFeMo9A recorded at room temperature and analyzed with triangular distributions. Figure 2 Raman spectra of hydrotalcite before and after Cr(VI) sorption. References [1] Kok-Hui Goh, Teik-Thye Lim, Zhili Dong. Application of layered double hydroxides for removal of oxyanions: A review Water Research 42, (2008) 1343-1368 [2] J. Das, D. Das, G. Prasad Dash, D. Prakasini Das and . Parida “Studies on Mg/Fe hydrotalcite –like compound (HTlc): Removal of chromium (VI) from aqueous solution” Intern. J. Environ. Studies 61 (5) (2004) 605-616 75
T05 THE ACIDITY AFFECTING THE SURFACE CHARGE OF FERRIHYDRITE/ZEOLITE COMPOSITE AND THE ABILITY TO REMOVE ARSENATE FROM AQUEOUS MEDIUM 76 C.Pizarro1,2, L. Gaete1,2, M.F. Albornoz1,2 , P. Sanchez1, J.D. Fabris3,4, M. Escudey1,2 and J.D. Ardisson5 1 Facultad de Química y Biología. Universidad de Santiago de Chile. Santiago, 725475. Chile. 2 Centro para el Desarrollo de la Nanociencia y Nanotecnología (CEDENNA). Santiago, 725475, Chile. 3 Departamento de Química - ICEx, UFMG. Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil. 4 Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM). Campus JK, 39100-00 Diamantina, MG, Brazil. 5 Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), Campus – Pampulha, 31170-130 Belo Horizonte, MG, Brazil *Corresponding author: e-mail: carmen.pizarro@usach.cl Keywords: pH effects, arsenic, composite ferrihydrite Topic: T05- Catalysis, Corrosion and Environment The effectiveness of adsorbent materials to remove arsenate polluting natural water bodies depends on the surface charge, crystalline structure and surface area of the adsorbing material. Ferrihydrite is a poorly crystalline iron oxide with high surface area and variable surface charge. It is reported the work relating the effect of the acidity of the aqueous medium affecting the surface charge and consequently the adsorption ability of ferrihydrite/zeolite composite to remove arsenate from aqueous medium. The composite was prepared with a natural zeolite coated with 23 mass% of ferrihydrite synthesized according to the procedure described by Schwertmann and Cornell [1]. The ferrihydrite and the composite samples were characterized for their specific surface area (SSA), hyperfine structure assessed with 57Fe Mössbauer spectroscopy, crystallographic features with powder X-ray diffraction (XRD) and also for some of their morphological aspects, with optical analysis. The 298 K - Mössbauer spectra (Figure 1 and Table 1) for these samples show an intense doublet of the characteristic paramagnetic Fe3+ in ferrihydrite [2]. The found SSA values for this ferrihydrite and for its composite were 261 ± 3 m2g-1 and 107 ± 3 m2g-1, respectively. The arsenate adsorption kinetics at both pH 7.5 and 4.5 follows a pseudo-first order model; the maximum adsorption is achieved after 120 min. Fitting data to the Langmuir model leads to a maximum of arsenate adsorption of 36.6 and 46.08 mg g-1 at pH=7.5, for the sole ferrihydrite and the composite, respectively. If the pH of the aqueous medium is adjusted to pH=4.5, rather away from the point of zero charge of ferrihydrite (pH = 8.0), the arsenate adsorption capacity of these materials increases significantly up to 56.28 and 86.03 g g-1, for the sole ferrihydrite and the composite samples, respectively. From these results, controlling the pH value is a critical condition to assure the suitable effectiveness of the adsorbing capacity of these materials with variable charge surface to optimize the arsenate removal from aqueous systems. Figure 1. 298 K-Mössbauer spectra for the ferrihydrite (Fh) and its composite (FhZ-23) Table 1. 57Fe hyperfine parameters for the ferrihydrite (Fh) and for the ferrihydrite/zeolite composite (FhZ-23) at 298K. δ(Fe) = isomer shift relative to Fe; 2ε = quadrupole shift and RA = relative subspectral area. Sample δ(Fe)/mm s-1 2ε/mm s-1 RA/% FhZ-23 0.34 0.67 100 Fh 0.33 0.65 100 References [1] Schwertmann U., Cornell R.M. (2003). Iron Oxides in the Laboratory. Preparation and Characterization.Editorial Wiley-VCH, second edition, pp 11. [2] Murad, E. (2010). Mössbauer spectroscopy of clays, soils and their mineral constituents. Clay minerals, Volume 45, Number 4, pp. 413–430. Acknowledgments: Work supported by DICYT-USACH 021242PA, CEDENNA FB-0807 (Chile), CNPq (grants # 487148/2013-4; 124629/2013-0 and 305755-2013-7) and FAPEMIG (Brazil). JDF is also indebted to CAPES (Brazil) for granting his visiting professorship at UFVJM under the PVNS program.
T06 MÖSSBAUER SPECTROSCOPIC STUDY OF CALCIUM SUBSTITUTION IN THE Sm1‐ xCaxFeO3‐δ (0.1 ≤ x ≤ 0.5) SYSTEM PREPARED BY SOL‐GEL BASED PECHINI METHOD 77 A. M. Huízar-Félixa, E. Legarrab, D. Meridab, F. Plazaolab, T. Hernández a Laboratorio de Materiales I, Centro de Laboratorios Especializados, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, Av. Pedro de Alba S/N, C.P. 66450, San Nicolás de los Garza, Nuevo León, México b Elektrizitate eta Elektronika Saila, Euskal Herriko Unibertsitatea UPV/EHU, p.k. 644, 48080 Bilbao, España . *Corresponding author: e-mail: tomas.hernandezgr@uanl.edu.mx Keywords: sol-gel processes; crystal structure; oxide materials; Mössbauer spectroscopy; vacancy formation; hyperfine interactions Topic: T06- Chemical Applications, Structure and Bonding Perovskite series Sm1-xCaxFeO3-δ (0.1 ≤ x ≤0.5) were obtained by sol-gel Pechini method. XRD analysis and Mössbauer spectroscopy were employed to characterize the synthesized perovskites. The system was found to be a pure phase with minimum distortion of the crystalline structure. The Mössbauer measurements (Figure 1) revealed the presence of Fe3+, Fe4+ and Fe5+ charge states. The presence of Fe5+ in all the samples confirms the occurrence of charge disproportionation (2Fe4+ → Fe3+ + Fe5+) at 293 K. The introduction of non-magnetic Ca atoms on Sm positions produces the appearance of several octahedral Fe3+ positions. For the samples with the lowest Ca content (x = 0.1, 0.2 and 0.3) the areas of the octahedral Fe3+ positions obey the binomial distribution indicating that the Ca atoms place randomly in Sm positions and the amount of Fe4+ is sufficient in order to avoid the formation of vacancies. In contrast, above 30% Ca the amount of Fe4+ cannot be increased, and for x=0.4 and x=0.5 the samples present oxygen vacancies, which results in tetrahedral Fe3+ positions. Figure 1. Mössbauer spectra of Sm1-xCaxFeO3-δ system (0.1 ≤ x ≤ 0.5). Grey sextets correspond to Fe3+ in octahedral positions, orange sextet corresponds to Fe3+ in tetrahedral position, blue and red sextets correspond to Fe3+ and Fe5+ due to charge disproportionation, green sextet corresponds to Fe4+ and brown singlets correspond to paramagnetic Fe3.5+.
T08 57Fe AND 119Sn MÖSSBAUER STUDY OF Fe DOPED SnO2 OBTAINED BY 78 MECHANICAL MILLING L.C. Sánchez1*, J. J. Beltrán2, J.A. Osorio2, E. M. Baggio- Saitovitch3 and C. A. Barrero2 1Grupo Avanzado de Materiales y Sistemas Complejos-GAMASCO, Universidad de Córdoba, Colombia. 2Grupo de Estado Sólido, Sede de Investigación Universitaria, Universidad de Antioquia, Colombia 3Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca. CEP 22290-180, Rio de Janeiro, Brasil. *Corresponding author: e-mail: luiscarlos@correo.unicordoba.edu.co Keywords: Fe doped SnO2, Mechanical milling, Mössbauer spectroscopy. Topic: T08- Magnetism and Magnetic Materials Powders of SnO2 doped with iron were prepared from mechanical alloying in a planetary ball mill Fritsch Pulverisette 5 and using like precursors: SnO2 and metallic iron (α-Fe). Were investigated as the structural and magnetic properties of products are affected, due to the influence of different conditions of milling such as: powder to ball weight ratio (1:20, and 1:40); time of milling (6, 12, 18 and 24 hours); speed of rotation of the support disc (250 and 390 rpm) and concentration of the dopant (1, 4 and 8 at%). All the millings were conducted to room temperature and atmospheric pressure. Additionally, a structural and Mössbauer analysis was made of the evolution of the pure and Fe doped SnO2 submitted to milling. The 119Sn Mössbauer spectra of the samples consist of two doublets. The parameters of the doublets are only assigned to the presence of Sn4+. The first doublet correspond well to those characteristics of bulk SnO2, while the second doublet can be associated with a much distorted Sn microenvironment due to a neighboring crystal defect like a vacancy (see Fig. 1). Figure 1. Room temperature 119Sn Mössbauer spectra of Fe (8% at.) doped SnO2, obtained by milling during 12 and 18 h. The 57Fe Mössbauer spectra of the samples consist of one or two doublets, and one sextet. The parameters of the first doublet are assigned to the presence of Fe3+ in octahedral sites, which suggest substitution of the Fe by the Sn in the structure of the SnO2 (Fig. 2). Additionally a second doublet was observed, whose parameters suggest the presence of Fe2+. Rodriguez Torres and coauthors [1] suggest the presence of states of oxidation Fe2+ and Fe3+ for the milled samples of SnO2 with α-Fe, which would correspond to iron ions with different environments. Of another part, the parameters of the sextet detect the presence of α-Fe, corresponding to the part of the powder that was not incorporated to the structure of the SnO2. By using density functional theory calculations, we explore the effects of Fe on the structural, electronic and magnetic properties of the samples. Figure 2. Room temperature 57Fe Mössbauer spectra of Fe (4 and 8% at) doped SnO2, obtained by milling during 12 h. References [1] C. E. Rodríguez Torres, A. F. Cabrera and F. H. Sánchez. Physica B 389 (2007) 176
T08 A MAGNETOMETRY AND MÖSSBAUER SPECTROSCOPY STUDY OF THE TRANSFORMATION OF FERRIHYDRITE WITH COBALT AS CATALYST 79 K. I. Camacho*1, J. Quispe- Marcatoma2,3, W. T. Herrera2,3, A. I. Martinez1, E. Baggio-Saitovitch3 1Centro de investigación y de estudios avanzados del Instituto Politécnico Nacional unidad Saltillo, Coahuila, México. C.P. 25000. 2Facultad de ciencias físicas, Universidad Mayor de San Marcos, Lima, Perú. 3Centro Brasileiro de Pesquisas Físicas, Río de Janeiro, 22290-180, Brazil. *Corresponding author: e-mail: kicamachoa@cinvestav.mx Keywords: Ferrihydrite, Hematite, Magnetite, Cobalt, NaHCO3, XRD, Mössbauer Spectroscopy, Magnetization. Topic: T08- Magnetism and Magnetic Materials. Iron oxides have been used for degradation of organic compounds in water with a reaction similar to the effected by peroxidase. Hematite and cobalt ferrite nanoparticles have shown a great capability for prussian blue degradation. Hematite and magnetite nanoparticles have been synthetized from the transformation of 2-line ferrihydrite (2LF), using cobalt dications as catalyst and NaHCO3 as pH-buffer. Cobalt ions with different percents of cobalt (RCo0%, RCo0.05%, RCo1%, RCo3%, RCo5%. RCo15% and RCo20%) were added, and the ferrihydrite transformation was followed by Mössbauer spectroscopy and magnetometry (figure 1). It was found that cobalt ions induce the formation of magnetite at higher percent and hematite is formed at lower percent. Additionally, the formation of other phases such as goethite and lepidocrocite was avoided during the transformations. On the other hand, magnetic measurements indicated that hematite growths with very low coercive fields that do not depends on the cobalt concentration. However, magnetite samples, where no clear difference between their XRD patterns is observed (see figure 1a for RCo15% and RCo20%), the magnetization measurements shown that cobalt strongly affects the coercive field in the samples. Mössbauer spectroscopy fittings confirm the formation of hematite and magnetite in each case, but small amounts of 2-line ferrihydrite were detected yet (figure 1b). References (1) Liu, H.; Ma, M.; Qin, M.; Yang, L.; Wei, Y. J. Solid State Chem. 2010, 183, 2045–2050. (2) Cornell, R. M.; Giovanoli, R. Polyhedron 1988, 7, 385–391. (3) Cornell, R. M.; Giovanoli, R. Clay Clay Miner. 1989, 37, 65–70.
Figure 1. a) XRD patterns, b) Mössbauer spectrum for the samples at room temperature. 80
T08 DETERMINATION OF THE RELATIVE RECOILLESS F‐FACTOR FOR THE ORTHOFERRITE NdFeO3 SYNTHETIZED BY SELF‐COMBUSTION METHOD 81 L.A Morales1, O. Arnache2, C. Barrero2, and G.A. Sierra1 1 Departamento de Materiales y Minerales, Facultad de Minas, Universidad Nacional de Colombia, Calle 75 # 79A-51, Bloque M17, Medellín, Colombia 2 Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia - UdeA, Calle 70 No. 52-21, A.A. 1226, Medellín, Colombia. *Corresponding author: e-mail: cbarrero@fisica.udea.edu.co Keywords: Orthoferrite, Relative F-factor, self- combustion. Topic: T08 - Magnetism and Magnetic Materials The NdFeO3 compound was synthesized by the self-combustion method. The Rietveld refinement of the XRD pattern proved the purity of the phase and it was fitted using the space group Pbnm, Perovskite type (see Fig.1). Using the Scherrer equation, the average crystal size was estimated to be 75.3 nm. The ZFC and FC curves showed an antiferromagnetic behavior, which was also evident in the M vs H curves at 300 K. Figure 1. Diffractogram and ICSD pattern of the NdFeO3 compound After the structural and magnetic analysis, this work also reports the room-temperature relative recoilless F-factor of the NdFeO3 compound. This was made by applying a method based on the correct determination of the two subspectral areas present in a mixture of known amounts of the compound under study and a standard sample [1], which in our case was iron powder. The procedure was repeated three times for different amounts of the compounds. The obtained spectra were thickness-corrected and fitted using the commercial software Recoil [2] (see Fig. 2). The relative recoilless F-fraction for the NdFeO3 with respect to α-Fe was calculated to be 1,15േ0.03, a result which compares reasonably well with that value predicted by the Debye model and the reported Debye temperatures for these two compounds.
Figure 2. Fitted Mössbauer spectra for the three amounts of the mixture NdFeO3 - αFe References [1] Oh, Sei J., and D. C. Cook. Journal of applied physics 85.1 (1999): 329-332. [2] K. Lagarec and D. G. Rancourt, Recoil: Mössbauer Spectral Analysis Software for Windows, version 1.0 (Department of Physics, University of Ottawa, Canada, 1998). 82
T08 EFFECT OF Co2+ IN STRUCTURAL AND MAGNETIC PROPERTIES OF COBALT FERRITES OBTAINED BY THE COPRECIPITATION METHOD 83 A. A.Velásquez1,*, S. Venegas1 and J.P.Urquijo2 1Grupo de Electromagnetismo Aplicado, Universidad EAFIT, A.A. 3300, Medellín, Colombia 2Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia, A.A. 1226, Medellín, Colombia *Corresponding author: avelas26@eafit.edu.co Keywords: Cobalt ferrites, Mössbauer spectroscopy, coprecipitation method Topic: T08- Magnetism and Magnetic Materials In this paper we study the effect of divalent cobalt on the structural and magnetic properties of cobalt ferrites, Fe3-xCoxO4, substituted at weight percentages of 5%, 10%, 15%, 20% and 30%, which were synthesized by the coprecipitation method. Several effects were observed as the Co2+ concentration increases in the starting solutions: X-ray diffraction measurements showed a sequential increasing of the lattice parameter, while room temperature Mössbauer measurements showed a progressive reduction of the spectral area of the Fe2.5+ sub spectrum relative to the area of the Fe3+ sub spectrum, as well as a reduction in the hyperfine magnetic field of the Fe2.5+ sub spectrum ions while the hyperfine magnetic field of the Fe3+ sub spectrum remained almost constant. The results suggest a progressive incorporation of ions Co2+ in the octahedral sites of ferrite, where they substitute Fe3+ ions, expanding the crystalline structure and promoting vacancy generation. Figure 1. Room temperature Mössbauer spectrum of the 5 wt.% Co2+ cobalt ferrite. References [1] Sorescu.Monica, Diamandescu.L., Tarabasanu-Mihaila.D., Materials Letters 59 (2005) 22-25 [2] Sorescu.Monica, Journal of Nanoparticle Research 4 (2005) 221 [3] Velásquez.A.A., Morales.A.L., Urquijo.J.P., Baggio.E., Hyperfine Interactions 203 (2011) 75-84ö
T08 Fe‐DOPED SnO2 NANOPOWDERS OBTAINED BY MECHANOCHEMICAL 84 ALLOYING AND THERMAL TREATMENT OF SnCl2 L.C. Sánchez1*, J. J. Beltrán2, J.A. Osorio2, E. M. Baggio- Saitovitch3 and C. A. Barrero2 1Grupo Avanzado de Materiales y Sistemas Complejos-GAMASCO, Universidad de Córdoba, Colombia. 2Grupo de Estado Sólido, Sede de Investigación Universitaria, Universidad de Antioquia, Colombia 3Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca. CEP 22290-180, Rio de Janeiro, Brasil. *Corresponding author: e-mail: luiscarlos@correo.unicordoba.edu.co Keywords: Tin oxide nanoparticles; Fe doping; Mechanochemical milling and thermal treatment. Topic: T08- Magnetism and Magnetic Materials In this work, Sn1-xFexO2 (x=0, 0.03, 0.05, 0.08 and 0.10) nanoparticles were synthesized by mechanochemical alloying of anhydrous SnCl2 (or SnCl2•2H2O), FeCl3 and Na2CO3, with NaCl added as diluents. The as-milled mixtures were subsequently heat treated at 600 °C during 3 hours, in air atmosphere, and finally washed with double deionized water. NaCl is used in order to improve the milling characteristics of the reactant powders. The mechanochemical processes was performed in a planetary ball mill Fritsch Pulverisette 5, using Cr-based stainless steel jars and balls of 12 mm in diameter. The rotation velocity of the disc was of 250 rpm, and the ball to powder ratio was of 20:1. Samples were milled for 3 and 12 hours in atmospheric conditions. The overall reaction is accounted for by: SnCl2 + Na2CO3 → SnO +2NaCl +CO2, and the heat treatment of the milled-product in oxygen is followed in order to oxidize SnO to SnO2 [1]. X-ray diffraction patterns of all Sn1-xFexO2 samples showed peaks due to the cassiterite phase of SnO2. The Raman spectra exhibit bands of SnO2, and the presence of hematite for some samples. Changes in the intensity, FWHM, area, and position of the vibrational bands with Fe doping concentration were observed. 57Fe Mössbauer spectra of Sn1-xFexO2 samples were composed of magnetic and paramagnetic signals (see Fig. 1). The paramagnetic signals pointed to an incorporation of the Fe3+ ions into the SnO2 crystallographic structure. It was found that by using anhydrous-SnCl2 and SnCl2•2H2O, the final product was a mixture of hematite plus Sn1-xFexO2, but hematite was less abundant for the former sample. 119Sn Mössbauer spectra for all samples indicated only the presence of Sn4+ in octahedral sites. Room temperature hysteresis loops for an impurity-free sample consisted of contributions coming from paramagnetic and ferromagnetic signals, which could be related to an inhomogeneous distribution of the iron ions in the crystallographic structure (see Fig. 2). Our results suggested that 3 hours of milling, instead of 12 hours, low iron concentrations and the use of anhydrous SnCl2, instead of SnCl2•2H2O, can give better conditions to produce impurity free samples. a) Figure 1: RT 57Fe Mössbauer spectra of Sn1-xFexO2 (x=0.03, 0.05, 0.08 and 0.10) samples obtained from SnCl2 for 12 h of milling time. b) Figure 2: RT hysteresis loop of Sn1-xFexO2 (x=0.03) sample obtained for 12 h of milling time. The experimental data, the fitted curve and the paramagnetic and ferromagnetic contributions are shown. References [1] H.M. Yang, Y.H. Hu, A.D. Tang, S.M. Jin, G.Z. Qiu, J. Alloys Comp. 363 (2004) 271.
T08 INTERACTION OF GOLD CLUSTERS WITH MAGNETITE NANOPARTICLES AND ITS 85 EFFECTS ON THE MAGNETIC PROPERTIES L. León Félix1, J. Mantilla, J. A. H. Coaquira1, M. A. R. Martinez1, M. Parise1, L. De Los Santos Valladares2, A. Bustamante3, V. K. Garg1, A. C. Oliveira1 and P.C. Morais 1Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília, DF 70910-900, Brazil. 2Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom. 3Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima, Perú. *Corresponding author: e-mail: lizbetlf@gmail.com Keywords: Au-coated magnetite nanoparticles, HRTEM, Mössbauer spectroscopy. Topic: T08- Magnetism and Magnetic Materials. The synthesis of core/shell iron oxide nanoparticles (NPs) with appropriate surface modification are of great interest in optical, magnetic and biomedical applications because of the unique combination of the nanoscale magnetic core and the functional shell. In special, gold (Au) coated magnetic NPs with high magnetic moment can be more efficiently stabilized and functionalized through the well-developed Au-S chemistry. Several methods have been developed to synthesize Fe3O4/Au composites attempting to control the particle size, shape, and surface properties [1]. In this work, we present the structural, microscopic, magnetic and hyperfine properties of Au-coated magnetite (Fe3O4) NPs. The uncoated Fe3O4 NPs were synthesized by the co-precipitation method and the gold coating was obtained by adding the gold precursor directly to the boiling solution of sodium citrate with the Fe3O4 NPs. The X-ray diffraction (XRD) data analysis confirms the formation of the spinel structure and Fe3O4 NPs with a mean crystallite size of ~8 nm. The XRD pattern of Au-coated Fe3O4 NPs shows extra peaks consistent with the formation of the gold phase. The mean particle size has been determined from high-resolution transmission electron microscopy images, which corroborates the mean crystallite size of the Au-coated Fe3O4 NPs. The saturation magnetization determined from magnetization vs. magnetic field curves for the uncoated NPs suggests the occurrence of magnetic disorder likely at the particles surface. However, the saturation magnetization increases for the Au-coated NPs which suggests that the gold coating partially reduces the magnetic disorder. Zero-Field-Cooled and Field-Cooled curves show features associated with a thermal blocking process of interacting particles. The decrease of the blocking temperature from TB= 119 K to 95 K after the gold coating suggests the weakening of the particle interactions. Room temperature Mössbauer spectrum shows features related to thermal relaxation of interacting magnetic moments in agreement with the DC magnetization results. Moreover, at 77K the Mössbauer spectra are well resolved using magnetic sextets, which are assigned to the Fe ions occupying tetrahedral and octahedral sites at the core and shell parts of the particle. Figure 1. The Rietveld refinement of the XRD patterns of the gold-coated Fe3O4 nanoparticles. The observed and calculated data are represented by the points and solid line, respectively. The Bragg reflections are also indicated. The HRTEM of the gold-coated Fe3O4 nanoparticles is shown in the inset. References [1] Oscar A. Loaiza, Elena Jubete, Estibalitz Ochoteco, German Cabañero, Hans Grande, Javier Rodriguez, Biosensors and Bioelectronics, 26 (2011) 2194–2200.
T08 LOW TEMPERATURE MÖSSBAUER STUDY OF Fe DOPED ZnO Ligia E. Zamora1, J. F. Exp Ajus Distri Fe2+ Fe3+ 20K 86 Piamba1, J. A. Tabares1 and G. A. Pérez-Alcázar1 1Grupo de Metalurgia y Teoría de Transiciones de Fase, Facultad de Ciencias, Universidad del Valle. Cali, Colombia. *Corresponding author: e-mail: ligia.zamora@correounivalle.edu.co Keywords: Fe doped ZnO, Ferromagnetic, Semiconductor, Mössbauer. Topic:T08- Magnetism and Magnetic Materials The Zn0.90Fe0.10O system was prepared by mechanical alloying at 24 h. The structural characterization of the sample was performed by X-ray diffraction and the pattern showed the würtzite structure of ZnO; and the bcc structure of α-Fe. The hyperfine parameters were obtained from Mössbauer spectroscopy. The Mössbauer spectra at room temperature shows that the samples present three components: a ferromagnetic, associated to Fe phase; and two paramagnetic, associated to the Fe atoms, which penetrate inside the ZnO matrix behaving as Fe3+ and Fe2+. The sample was cooled to 20 K and spectra were taken at different temperatures. The Magnetic properties were investigated with Vibrating Sample Magnetometer (VSM) at room temperature, which detected a ferromagnetic behavior, with coercive field of 330 Oe. The behavior of resistivity was measured as a function of temperature. Figure 1 shows the temperature dependence of normalized resistivity for ZnO in the range 20 to 300K. Also, it presents a peak at 50 K, which is associated to a magnetic transition. 0 50 100 150 200 250 300 1,0 0,8 0,6 0,4 0,2 0,0 Temperature (K) 24h R/Rmax Figure 1. Temperature resistivity normalized by Zn0.90Fe0.10O Mössbauer spectra were collected decreasing the temperature, in Figure 2 the spectrum is shown at 20K; the other spectra are similar. In Figure 3 is showed the behavior of the mean hyperfine field obtained from the fitting the spectra. 1,00 0,98 -9 -6 -3 0 3 6 9 V (mm/s) Figure 2. Mössbauer spectra at 20K for Zn0.90Fe0.10O
Distribution 0 100 200 300 87 340 335 330 325 <Bhf> Temperature (K) Figure 3. Mean Hyperfine Field as a function of temperature for Zn0.90Fe0.10O From the fit of the spectra the mean hyperfine magnetic field, Bhf, versus temperature was obtained and illustrated in figure 3. It is observed a kink at 50 K, which is associated to a reentrant spin glass- ferromagnetic transition (1), in according with results obtained in Resistivity. Distribución 0 100 200 300 340 335 330 325 <Bhf> Temperatura (K) Distribución 0 100 200 300 340 335 330 325 <Bhf> Temperatura (K) References [1] J. E. Ramos, M. Montero-Muñoz, J. A. H. Coaquira, and J.E. Rodrígez-Páez. Journal of Applied Physics 115, 17E123 (2014).
T08 MAGNETIC AND STRUCTURAL EVOLUTION OF Nd2Fe14B NANOPARTICLES 88 8j1 16k1 8j2 Nd1.1Fe4B4 Pure 10% Co Relative Transmision 20% Co 25% Co -10 -5 0 5 10 Velocity [mm/s] DOPED WITH Co DURING SURFACTANT‐ASSISTED BALL‐MILLING J. S. Trujillo Hernandez1*, J. A. Tabares1 and G.A. Pérez Alcázar1 1Departamento de Física, Universidad del Valle, Meléndez, A. A. 25360, Cali, Colombia. *Corresponding author: e-mail: trujillohernandezjuansebastian@gmail.com Keywords: Mössbauer Spectrometry, X-ray Diffraction, Vibrating Sample Magnetometry, NdFeB magnets. Topic: T08- Magnetism and Magnetic Materials In the search of novel nanosized magnetic materials with enhanced magnetocrystalline anisotropy and energy product, the study of rare-earth based nanostructures is becoming more intense. Materials with large coercivity like Nd2Fe14B improve their physical properties in the nanoscale and may be coupled with other magnetically softer compounds such as α-Fe or Fe3B to fabricate high-performance permanent magnets at a lower cost [1]. However, chemical methods, used in the synthesis of various magnetic nanoparticles, have a limited success in the case of complicated hard phase rare-earth compounds [2]. High-energy ball-milling is a simple, inexpensive and efficient method for size reduction of particle size of nanocrystalline powders. In this work, powder produced by arc melting of the alloy Nd16(Fe76-x Cox)B8 with x = 0, 10, 20 and 25 (size distribution under 20 μm) was milled in a high-energy planetary ball-mill (Fritsch Pulverisette 5 with hardened steel balls) at a rotational speed of 300 rpm. The milling was performed in a protective argon atmosphere with the ball-to-powder weight ratio of 20/1 for milling times varying from 1 to 2 h. Hexane (55% of powder weight) was introduced in the mill as a solvent together with oleic acid (12% of powder weight) as surfactant. The powders obtained after milling was washed with ethanol. X-ray diffraction (XRD), Mossbauer spectroscopy (MS), and Vibrating Sample Magnetometry (VSM) measurements were performed in order to characterize the properties of the obtained samples. A PanAnalytical diffractometer with a Cu anode, a constant acceleration mode Mössbauer spectrometer with a 25 mCi 57Co (Rh) source, and a PPMS of Quantum Design were used, respectively, to obtain these measurements. Figure 1 shows the Mössbauer spectra for the above mentioned compositions. Mössbauer Spectrometry shows the ferromagnetic behavior (seven sextets) associated to the soft and hard magnetic phases and one paramagnetic component (doublet) associated to the minority Nd1.1Fe4B4 phase. All samples present a hard magnetic behavior. The increase of Co content in these samples does not improve the hard magnetic behavior. Figure 1. MS for samples at different concentration of Co. Seven magnetic sites and a doublet need to be included.
Figure 2. AFM image (500nm x 500nm) of the Nd2Fe14B doped with Co. References [1] E. F. Kneller and R. Hawig, IEEE Trans. Magn. 27 (1991) 3588.E. [2] Ruiz Saldarriaga, Thesis: Efecto de altas concentraciones de níquel en las propiedades magnéticas y estructurales de la aleación Nd16Fe76B8.. This work was partially financed by “Centro de Excelencia de Nuevos Materiales CENM-Univalle. 89
T08 MAGNETIC BEHAVIOR OF THE FeSi (sc) PHASE WITH TEMPERATURE 90 VARIATION J. F. Piamba1*, G.A. Pérez Alcázar1 1Departamento de Física, Universidad del Valle, A.A. 25360, Cali, Colombia. *Corresponding author: e-mail: jeferson.piamba@correounivalle.edu.co Keywords: Mössbauer spectroscopy, FeSi (sc), XRD. Topic: T08- Magnetism and Magnetic Materials. Binary alloys have been widely studied, principally Fe-Si alloys [1, 2, 3], which present the FeSi simple cubic (sc) ordered structure with a paramagnetic behavior [4]. In this work we present the study of Fe50Si50 system prepared by melting and heat treatment. This process was utilized to obtain the sc crystalline structure with high structural order. X-ray diffraction found that the system present a FeSi mono-phasic sc structure, with crystallite size 138.9±0.5 (nm), lattice parameter 4.490±0.003 (Å) and high structural order, evidenced by the presence of super structure lines. Fig. 1 shows the XRD pattern of the prepared sample, in which the most intensive super structure line corresponds to the diffraction of the (312) family planes. This indicates that the sample presents a high structural order, and that the melting and heat treatment were appropriated. Exp. Adj Bkg FeSi(sc) 20 40 60 80 Intensity (a.u.) 2 º (312) Figure 1. XRD pattern of Fe50Si50 sample obtained by melting and heat treatment. Scanning electron microscopy (SEM) showed that the melting process generated an uniformity and homogeneity of material. The hysteresis loop result shows that the sample has a coercive field Hc = 25.9 ± 0.2 (Oe) classifying it as magnetically soft and that the predominant interaction inside the material is dipolar, main feature used in magnetic recording devices. Mössbauer spectroscopy results showed that the samples exhibit in the whole range of measure temperatures a paramagnetic behavior (see Fig. 2a). Although there is no change in the magnetic behavior of the system, their hyperfine parameters vary, as seen in Fig. 2b. It can be observed an increase of IS and QS with decreasing of temperature. 20K 120K -4 -2 0 2 4 Relative Transmission 300K V (mm/s) (a) 0.8 IS 0 50 100 150 200 250 300 0.6 0.4 0.2 QS IS, QS (mm/s) Temperature (K) (b) Figure 2 Mössbauer spectra (a) and behavior of hyperfine parameters of the FeSi phase as a function of Temperature. The soft magnetic behavior detected by VSM measurement contrast with the paramagnetic behavior detected by Mossbauer and this is explained by the nanostructured character of the sample, in which the atoms of the surface and of the boundary lost its coherence and can behave as ferromagnetic.
References [1] A. García Escorial, P. Adeva, M.C. Cristina, A. Martín, F. Carmona, F. Cebollada, V.E. Martín, M. Leonato, and J.M. González, Mater. Sci. Eng. A 134 (1991) 1394. [2] E. Gaffet, N. Malhoureux, and M. Abdellaoui., J. Alloys Compds., 194 (1993) 339 [3] Z.B. and S.T., Acta Materialia, 53 (2005) 1233 [4] J. F. Piamba, R. R. Rodríguez, and G.A. Pérez Alcázar, Rev. Mex. Fis. S57 (2) (2012) 88 91
T08 MAGNETIC BEHAVIOR OF TWO SPHERICAL NANOPARTICLES WITH DIPOLAR 92 INTERACTION AND INTERNAL ISING INTERACTIONS A.M. Schönhöbel1,* and W. R.Aguirre-Contreras1 1Grupo de Metalurgia y Transiciones de Fase, Facultad de Ciencias Naturales y Exactas, Universidad del Valle. Cali, Colombia *Corresponding author: e-mail: ana.schonhobel@correounivalle.edu.co Keywords: Hard spherical nanoparticles, Monte Carlo simulation, Metropolis algorithm, dipolar interaction, exchange interaction Topic: T08- Magnetism and Magnetic Materials Using a three-dimensional Ising model and Monte Carlo simulations by Metropolis algorithm, we have studied the temperature-dependent magnetization of two ferromagnetic and antiferromagnetic nanoparticles on a body-.centered cubic lattice. We have considered identical nanoparticles with spherical geometry and they are interacting via dipolar forces. The effect of dipolar forces and the exchange couplings on the critical behavior are investigated. Our results present rich critical behavior, which include Paramagnetic-Ferromagnetic phase transitions. It is also found that nanoparticles size and the dipolar force between them are related with the appearance of more than a unique critical point. References [1] N. N. Phuoc, T. Suzuki, R. W. Chantrell and U. Nowak. Phys. stat. sol. (b). V 244 (12) (2007) 4518 [2] E. De Biasi, C.A. Ramos, R.D. Zysler, D. Fiorani. Physica B. V 372 (2006) 345 [3] A. Weizenmann and W. Figueiredo. Int. Journ. of Mod. Phys. C. V. 23 (08) (2012) 1240006–1 [4] A. Weizenmann and W. Figueiredo. Phys. A, 389:5416, (2010). [5] K. Trohidou and M. Vasilakaki. Acta Phys. Polonica A. V. 117 (02) (2010) 374
T08 MAGNETIC ORDER STUDY OF THE INTERMETALLIC FeGa3‐xGex SINGLE 93 CRYSTALS BY MÖSSBAUER SPECTROSCOPY J. Munevar1,2, H. Micklitz1, E. M. Bittar1, M. Cabrera-Baez2, M. A. Avila2, R. Ribeiro2, Y. J. Uemura3, E. Baggio- Saitovitch1 1Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil. 2) Departamento de Fisica, Universidade Federal do ABC, Santo Andre, Brazil 1Department of Physics, Columbia University, USA *Corresponding author: e-mail: munevar@cbpf.br Keywords: Intermetallic compounds, quantum critical point Topic: T08- Magnetism and Magnetic Materials The study of the magnetic semiconducting materials has gained attention due to their potential technological applications, besides the new physics involved. The FeGa3 compound is a very well known semiconductor with an energy gap of about 0.5 eV, caused by a hybridization between the Fe d and the Ga p states [1]. Doping with electrons via chemical substitution of the Ga by Ge leads to a change in the magnetic order, going from diamagnetism to ferromagnetism, reaching transition temperatures as high as 80 K. The purpose of this work is to study the magnetic properties via magnetization measurements and Mossbauer spectroscopy, where spectra for different compositions and at different temperatures and external fields were obtained. For samples showing Ge concentration below 0.13, there is no magnetic order as expected, and uSR measurements show an increase in the relaxation rate only at very low temperatures. Above this concentration, antiferromagnetic order is observed at low fields, and for fields as high as 1kOe is observed a ferromagnetic order. We also observe the magnetic behavior from Mossbauer spectroscopy, and a thorough analysis for spectra with zero field and external field will be presented. These results confirm the onset of magnetic correlations for doping above the value reported close to the quantum critical point. It is also indicating that exists some correlations between Fe moments induced by the substitution, either by adding more electrons to the Fermi surface or by the distortion of the lattices. A discussion about the nature of the ferromagnetic order will be presented. References [1] K. Umeo, Y. Hadano, S. Narazu. T. Onimaru, M. A. Avila, T. Takabatake, Phys. Rev. B textbf{86}, 144421 (2012).
T08 MAGNETOTRANSPORT PROPERTIES OF (Fe AND Ni)‐DOPED In2O3 POWDERS 94 OBTAINED BY SOLID STATE REACTION METHOD L.C. Sánchez1*, O. Arnache2, C. Ortega1, L.A. López1 and L. Ensuncho1 1Grupo Avanzado de Materiales y Sistemas Complejos-GAMASCO, Universidad de Córdoba, Montería - Colombia. 2Grupo de Estado Sólido, Instituto de Física, Calle 70 No. 52-21, A.A., , Universidad de Antioquia - UdeA, Medellín- Colombia *Corresponding author: e-mail: luiscarlos@correo.unicordoba.edu.co Keywords: Indium oxide nanoparticles; Transition metal doped; Solid State Reaction Method. Topic: T08- Magnetism and Magnetic Materials Indium Oxide (In2O3) is a transparent and dielectric material with a direct band gap of 3.75 eV, which has a wide variety of technological applications.. During recent years, the doping mechanism by transition metal (TM) impurities in In2O3 is considerably attractive due to its integration of physical properties (optical, electronic and magnetic) into one single material. This class of materials are called diluted magnetic semiconductors – DMS (or semimagnetic semiconductors). From viewpoint of magnetism, DMS system have attracted great interest for fundamental research and applications due to coexistence of high temperature magneticsm and semiconducting properties. The origin of ferromagnetism in TM-doped semiconductors has been controversial and has been explained by different mechanisms such as carrier-mediated interaction. However, in semiconductors with low carrier densities such as oxides, the novel type of magnetism can be explained by magnetic polaron mechanism. In this model, the spins of magnetic dopants incorporated into the semiconductor lattice interact through a donor-impurity band, formed by lattice defects such as oxygen vacancies. Coey et al.[1] explain the spin alignment of the 3d transition-metal cations by the coupling of their spins, which are antiparallel to the spin of donor electrons. Because of this coupling, all spins within this expanded orbit are aligned. Because of the overlap of different orbits, an impurity band is formed, aligning a huge number of 3d magnetic spins parallel, resulting in ferromagnetism. In the framework of this theory, not only the dopant concentration but also the number of donor electrons must be quite large to obtain ferromagnetism. Experimentally, there is much indirect evidence that the ferromagnetism is related to defects [2]. In this work In2-xTMxO3 (TM=Fe and Ni) polycrystalline samples with x=5% were prepared by a conventional solid state reaction method. Starting materials of In2O3 , Fe2O3 , α-Fe and NiO of high purity. Two different sources of Fe were used in order to obtain the Fe-doped In2O3. The appropriate amounts of powders were first weighted and mixed by milling for 10 h in a planetary ball mill, then sintered at 900 °C for 12 raising the temperature slowly in a controlled furnace in an air atmosphere. After that, the reacted material was ground in a mortar, pressed into rectangular shaped pellets and fired at 1100 °C for 12 hours. Phase purity and structural parameters were analyzed by means of x-ray diffraction (XRD) analysis technique. Structure refinements were carried out employing Rietveld analysis using Fullprof software. The refinement results confirm that Fe and Ni ions preferentially occupy the In3+ sites in all doped samples. Magnetic properties as a function of temperature at ZFC and FC from 5 to 300K of the pellets were measured by using VSM option in a Physical Properties Measurement System (PPMS, Quantum Design). Room temperature 57Fe Mössbauer Spectroscopy to probe the local magnetic environment prevailing around the Fe sites and also to determine the oxidation state of Fe in the In2O3 matrix have been recorded. Finally, to understand the magneto-transport correlations in those semiconductors we present a discussion of the electrical resistivity and Hall effect properties. References [1] J. M. D Coey, M.Venkatesan, C. B. Fitzgerald, Nat. Mater. 4 (2005) 173. [2] R.K. Singhal, A. Samariya, Sudhish Kumarb, S.C. Sharma, Y.T. Xing, U.P. Deshpande,T. Shripathi, E. Saitovitch, Appl. Surf. Sci. 257 (2010) 1053.
T08 STUDY OF MAGNETIC AND STRUCTURAL PROPERTIES DURING DEPOSITION OF 95 THIN FILMS TB0.257FE0.743. D. A. Granada1, Y. A. Rojas1, H. Rodríguez1, D. Oyola Lozano1, D. Betancourth1. 1 Laboratorio de Ciencia de Materiales y Tecnología plasma, Universidad del Tolima- Barrio Santa Helena - Ibagué, Colombia *Corresponding author: e-mail: dalagranada@gmail.com; dagranadar@ut.edu.co. Keywords: Stainless steel, point defects, CXMS Topic: T08- Magnetism and magnetic materials. The amorphous alloys of rare earth and transition metals (TR-MT), are of great interest to study the influence of structural disorder and the content of the TR in the basic magnetic properties. It is known that the exchange interactions between TR and MT originate a parallel or anti-parallel alignment of the moments of the TR with the time of MT, and the structural disorder can be caused by heat treatment during the preparation of alloys or substrate temperature during deposition of the films [1]. In the present study the influence of the substrate temperature on the magnetic and structural properties of thin films are reported Tb0.257Fe0.743 composition grown by DC sputtering on glass substrates.The substrates are subjected to temperatures of 100K, 300K and 500K. Structural properties from Diffraction Rays x (see fig.1) were investigated, the magnetic properties were investigated by Mössbauer spectroscopy at room temperature, View (fig.2). The Mössbauer spectra identified that increases in temperature increased quadrupole interactions giving greater paramagnetic character indicating the contribution of Tb to Fe environment. From the hysteresis loop of each film depending on the temperature of 5K, 80K and 300K View (fig.3); identified that the thin films are magnetically soft to very narrow hysteresis cycles, which have values of coercive fields from 5OE to 250Oe. Also, it was observed that the increase of the substrate temperature during deposition of the thin films will increase the degree of crystallinity. 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 9 0 0 0 8 0 0 0 7 0 0 0 6 0 0 0 5 0 0 0 4 0 0 0 3 0 0 0 2 0 0 0 1 0 0 0 intensity(U.A) 2  T e m p . = 1 0 0 K T e m p . = 2 0 0 K T e m p . = 3 0 0 K T e m p .= F it. T b N T b F e Fig.1. Pattern Diffraction Rays x, to thin films at 100K, 300K and 500K. -10 -8 -6 -4 -2 0 2 4 6 8 10 1,004 1,002 1,000 0,998 0,996 1,002 1,000 0,998 1,004 1,002 1,000 0,998 0,996 0,994 exp total fit1 Temp. 100K 0,996 Temp. 300K exp total fit1 0,994 Temp. 500K exp total fit1 Relative Transmission V [mm/s] Fig.2. Mössbauer Spectroscopy, to thin films at 100K, 300K and 500K.
-20000 0 20000 96 50 0 -50 -2 0 0 0 0 2 0 0 0 0 M (emu/g) H (O e ) 9 K 9 0 k 3 0 0 K M (emu/g) H (Oe) 100K 300K 5 0 0 K Fig. 3. Hysteresis Loops, of thin films of 100K, 300K and 500K, taken at a temperature of 80K. References [1] Malmhal R. l. (1987). Low-noise terbium-doped fibre amplifier operating at 1.54μm. Journal Appl. Phys 23: 1026-1028.
T08 STRUCTURAL, MAGNETIC AND MECHANICAL HARDNESS CHARACTERIZATION OF THE ALLOY Nd16 (Fe76‐x Nix) B8 WITH x = 0, 10, 20 AND 25 Observed Calculated Pure 10% N i 20% N i 25% N i 20 30 40 50 60 70 80 90 2  [Degrees] 97 J. S. Trujillo Hernandez1 J. A. Tabares1*, E. Ruiz Saldarriaga1, L. Zamora1, W. Aguirre1 and G.A. Pérez Alcázar1 1Departamento de Física, Universidad del Valle, Meléndez, A. A. 25360, Cali, Colombia. *Corresponding author: e-mail: jesus.tabares@correounivalle.edu.co Keywords: Mössbauer Spectrometry, X-ray Diffraction, Vibrating Sample Magnetometry, NdFeB magnets. Topic: T08- Magnetism and Magnetic Materials The compound of neodymium-iron-boron Nd2Fe14B approximate formula provided the best combination of magnetic and thermal properties of permanent magnets. Furthermore the Nd2Fe14B is surrounded by a magnetically soft material, for example α-Fe or Fe3B, showing an increase in the magnetic remanence caused by the exchange interaction between the two phases. This exchange interaction between the two phases occurs when the size of the phases is in the nanometer scale, of the order of 20 nanometers. Previous work [1] suggest alloy system Nd16 (Fe 76-x Nix) B8 allows to get the Nd2Fe14B as majority phase with nanometer size. In this work, samples of the alloy Nd16 (Fe 76-x Nix) B8 with x = 0, 10, 15, 20 and 25 were produced by arc melting and heat treated at 1073 K during 30 minutes and then quenched in ice water mixture. X-ray diffraction (XRD) (PanAnalytical, Cu anode), Mossbauer spectroscopy (MS) (constant acceleration mode with a 25 mCi 57Co (Rh) source) and Vibrating Sample Magnetometry (VSM) (Quantum Design, PPMS) were used in order to characterize the properties of the obtained samples. Microhardness tests were performed too. Figure 1 shows the XRD patterns for nickel varying concentrations. The system presents the hard Nd2Fe14B and the Nd1.1Fe4B4 phases for samples with x = 0, 10 and 20. When concentration increases to x = 10, 20 and 25 the NdNi2 and Nd2O3 phases appears. Crystallite size ranged between 10 to 100 nm. Figure 2 shows the Mössbauer spectra for the above mentioned compositions. There are seven sextets associated to the soft and hard magnetic phases and one doublet associated to the minority Nd1.1Fe4B4 phase, just identified by XRD. Magnetometry results allowed establish all samples present a hard magnetic behavior. The increase of Ni content in these samples does not improve the hard magnetic behavior but decrease the crystallite size of the hard phase. All samples improved hardness with increasing Ni. Intensity [a.u.] Figure 1. XRD patterns varying Ni concentrations. Pure sample pattern is include too.
 j1  Fe 25% N i Figure 2. MS for samples at different concentration of Ni. Seven magnetic sites and a doublet need to be included. References [1] E. Ruiz Saldarriaga, Thesis: Efecto de altas concentraciones de níquel en las propiedades magnéticas y estructurales de la aleación Nd16Fe76B8 [2] Rajasenkhar M., Akhtar D., Raja M. M. and Ram S., J. Magn. Magn. Mater., 320, (2008) 1645-1650. [3] Dai S., Morrish H., Zhou X. Z., Hu B. P. and Zhang S. G., J. Applied Physics, 63, (1988) 3722. This work was financially supported in part by “Centro de Excelencia de Nuevos Materiales CENM-Univalle. 98  k1  j2 Nd1 .1Fe4B 4 Pure 10% N i Relative Transmission 20% N i -10 -5 0 5 10 Velocity [mm/s]
T08 STUDY OF MAGNETIC PROPERTIES OF THE Mn3O4 MAGNETIC COMPOSITES 99 FOR APPLICATION IN WASTEWATER TREATMENT Isabel Cristina Souza Dinóla1, Gabriela Cordeiro Silva2 1 FUCAPI- Manaus -Amazonas 2 –Cefet – Belo Horizonte - Minas Gerais Composites with magnetic properties have been synthesized by means of the deposition of manganese oxide, Mn3O4, precipitated by using O2, onto magnetic particles. The magnetic particles in the composites form agglomerates with Mn3O4 particles. Solid-liquid separation by means of the application of the magnetic field is possible. The application of the magnetic composite in the oxidative adsorption of As3+ was evaluated. During the Arsenic oxidation-adsorption process, iron is not released and part of the Mn (II) released to solution is being adsorbed or precipitated, or both, which implies in a less contaminants release to solution. The general aim of the present work is to study the Mn3O4 magnetic composites in the application in wastewater treatment using several spectroscopic techniques like Mossbauer and Raman techniques to investigate the oxidation states of this composite improving our knowledge about the arsenic interactions with Mn3O4.
T08 SYNTHESIS AND CHARACTERIZATION OF MAGNESIUM FERRITES 100 NANOPARTICLES L. León Félix1, J. Mantilla1, M. A. R. Martinez1 and J. A. H. Coaquira1 1Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília, DF 70910-900, Brazil. *Corresponding author: e-mail: lizbetlf@gmail.com Keywords: Magnesioferrite, Mössbauer spectroscopy, sol-gel method. Topic: T08- Magnetism and Magnetic Materials Magnesium ferrite (MgFe2O4) is one of the most important members of the spinel family. Because of its small magnetocrystalline anisotropy, the superparamagnetic properties are still present at relatively low temperatures and/or high magnetic fields. MgFe2O4 is a n-type semiconducting material and apart from the magnetic and electronic applications, it has been widely applied in catalyst and sensors technology [1]. In this work, we present the study of MgFe2O4 nanoparticles (NPs) synthesized by colloidal suspension of magnesium nitrate hexahydrate (Mg(NO3)2.6H2O) in gelatin solution and using the sol–gel method. After the gel formation, the samples were annealed for 4 h at 350, 450, 550 650 and 850°C in air atmosphere. The X-ray diffraction (XRD) data analysis confirms the formation of only the spinel type structure of MgFe2O4 NPs. The mean crystallite size shows an increase by increasing the annealing temperature from 8 to 28 nm. The mean particle size has also been obtained from high-resolution transmission electron microscopy images, which corroborates the mean crystallite size. The Mössbauer spectroscopy measurements of MgFe2O4 NPs were performed at 77 K and room temperature. Room-temperature Mössbauer spectra of samples annealed at temperatures below 550°C show only a central doublet which suggests the occurrence of a superparamagnetism. However, Mössbauer spectra of samples annealed with temperatures above 650°C show a central doublet and collapsing sextets revealing the occurrence of the thermal relaxation of magnetic moments. At 77 K, Mössbauer spectra of samples annealed at temperatures below 550°C show also the presence of a central doublet and collapsing sextets. However, Mossbauer spectra of samples annealed at temperatures above 650°C show well defined sextets which evidence that the thermal relaxations effects observed at higher temperatures are no longer present. Figure 1. Room temperature XRD patterns of MgFe2O4 samples calcinated at different temperatures. The observed and calculated data are represented by the points and solid line, respectively. The Bragg reflections are also indicated. References [1] Zhengsong Lou, Minglong He, Ruikun Wang, Weiwei Qin, Dejian Zhao, and Changle Chen, Inorg. Chem. 2014, 53, 2053−2057.
T08 SYNTHESIS AND CHARACTERIZATION OF MAGNETIC FLUID CoFe2O4 WITH 101 OLEIC ACID AND TWEEN 80 J. L. López1, C. Carioca Fernandes1, J. H. Dias Filho2, R. Paniago3 and K. Balzuweit3 1Centro de Ciências Biológicas e da Natureza, Núcleo de Física, Universidade Federal do Acre, Rio Branco, AC 69915-900, Brazil. 2) Departamento de Ciências Exatas, Universidade Estadual de Montes Claros, 39.401-089, Minas Gerais, Brazil. 3) Departamento de Física, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Brazil. *Corresponding author: e-mail: jorge0503@gmail.com Keywords: Magnetic Nanoparticles, CoFe2O4, Topic: T08- Magnetism and Magnetic Materials CoFe2O4 magnetic nanoparticles were prepared by co-precipitation from FeCl36H2O and Co(NO3)26H2O aqueous solutions using NaOH and methylamine as precipitating reagents. The nanoparticles have an average size of 10 and 7 nm and exhibit superparamagnetism at room temperature. The nanoparticles were used to prepare a water-based magnetic fluid using oleic acid and Tween 80 as surfactants. The morphology, structure, magnetic properties and composition of CoFe2O4 magnetic nanoparticles coated with oleic acid and Tween 80 were examined. The stability and magnetic property of the magnetic fluid were also characterized. Aqueous samples were studied by Mössbauer spectroscopy and magnetic susceptibility in the range of 4.2–250 K. The saturation magnetization (Ms) at 4.2 K was determined from M vs 1/H plots by extrapolating the value of magnetizations to infinite fields, to 20 and 25 emu/g in both samples and coercivity to 50 and 65 Oe, respectively. The low saturation magnetization values were attributed to spin non-collinearity predominantly at the surface [1]. From the magnetization measurements a magnetic anisotropy energy constant (K) of 2.5×105 and 4×105 J/m3 were calculated. CoFe2O4 spectra at room temperature showed a doublet due to superparamagnetic relaxation and two sextets at low temperature for the sample with the smaller diameter. The sample shows a larger-diameter lower relaxation spectrum at room temperature. The line form in spectra Mössbauer vary with the temperatures it was simulated using a model of superparamagnetic relaxation of two levels (spin ½) and theory stochastic [2]. We assume for the particle diameters a probability distribution function of log-normal type and it was taken into account a dependence of the magnetic transition temperature on particle diameter. References [1] J. L. López, H. –D. Pfannes, R. Paniago, J.P. Sinnecker, M.A. Novak, J. Magn. Magn. Mater, 320 (2008) e327. [2] H.-D.Pfannes, J.H.Dias Filho, R. Magalhães Paniago, J. L.López, R. Paniago, Brazilian Journal of Physics, 31 (3), (2001) 409.
T08 SYNTHESIS, STRUCTURAL AND MÖSSBAUER SPECTROSCOPY 140 120 100 80 60 40 20 Exp. data Ajuste to 2 sextetos 1 sexteto 2 sexteto 102 CHARACTERIZATION OF NiFeO3 Nanoparticles J. Mantilla1,2, L. León Félix1, V.K. Grag1, A.C. de Oliveira1, J. A. H. Coaquira1 1Universidade de Brasília, Instituto de Física, Núcleo de Física Aplicada, Brasília, DF, CEP 70910-900. 2Laboratorio de caracterización de muestras, Facultad de Ciencias Escuela de Fisica, Universidad Central de Venezuela *Corresponding author: e-mail: mantilla52@gmail.com Keywords: Nanoparticles; Superparamagnetism; Surfactant; Sol-Gel Topic: T08- Magnetism and Magnetic Materials In this work, we present the study of NiFeO3 nanocrystalline syntnthesized by sol gel (critrate method) with calcining temperature of 600°C for 6 h [1]. The structural properties and crystallite sizes are determined by X-ray diffraction (XRD) technique. The hyperfine properties are characterized by Mössbauer spectroscopy and using Transmission Electron Microscopy (TEM) images was determined the size and size distribution of prepared particles. The X-diffraction pattern of the calcined powder was synthesized using this route and it shows that the final product is NiFeO3 with the cubic perovskite structure. The size of particles was determined by Scherrer formula. The average size were found to be 43, 5 nm. 20 30 40 50 60 70 0 Relative frenquecy (%) Particle size (nm) Do = 39.4 nm  = 0.28 Figure1. (a) TEM images of NiFeO3: scale bar 0,250 μm. (b) particle size distributions measured from TEM images The Fig. (1.a) shows the TEM images of NiFeO3 nanoparticles calcined at 600°C and the distribution of these nanoparticles are shown in the Fig. (1.b). The distribution seems to be symmetric (Gaussian) about 39,4 nm. The Mössbauer spectroscopy measurements of NiFeO3 nanocrystalline were performed at 77 K and room temperature as shown Fig (2). The Mössbauer spectras in Fig. 2 were well-fitted with two sextet. Table I shows the results of the hyperfine parameters corresponding Mössbauer spectra In the spectras are observed the presence of a well-developed magnetic order presenting with slightly asymmetrical lines due the existence of different magnetic environments Fe positions within the perovskite structure. T=297 K NiFeO3 T=77 K -10 -5 0 5 10 Relative transmission (a.u.) Velocity (mm/s) Figure 2. 57Fe Mössbauer spectra of NiFeO3 performed at 298 K and 77 K
Table I: Mössbauer hyperfine parameters: hyperfine field Bhf, isomer shift δ and quadrupole shift QS for sample. 103 Structure Temp. (K) Bhf (T) IS (mm/s) QS (mm/s) NiFeO3 298 52,08 0,36 -0,01 48,63 0,24 -0,01 77 54,9 0,47 -0,01 50,87 0,35 -0.01 References [1] Brinker C.J and Scherer G.W. Sol-Gel Sciences the Physics and chemistry of Sol-Gel processing. Academic Press, San Diego 1990.
T10 57Fe‐MӦSSBAUER STUDY OF IRON‐CONTAINING SODA LIME ALIMINOSILICATE GLASS WITH VISIBLE‐LIGHT ACTIVATED PHOTOCATALYTIC EFFECT -10 -5 0 5 10 Velocity / mm s -1 Fig.1 FeMS of heat-treated 50NCFS8A glass 104 Y. Iida, S. Kubuki, K. Akiyama and T. Nishida 1 Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi- Oji, Tokyo 192-0397, JAPAN 2 Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN *Corresponding author, e-mail: kubuki@tmu.ac.jp Keywords: photocatalyst, soda lime aluminosilicate glass Topic: T10- Catalysis, Corrosion and Environment 1. Introduction Anatase type TiO2 is well known as a photocatalyst which is activated by UV light with the wavelength () of shorter than 388 nm [1]. Recently, visible light activated photocatalysts have been investigated because of the higher effectiveness. Kubuki et al. reported that iron-containing soda lime silicate glass after heat treatment exhibited visible light activated catalytic ability due to precipitated -Fe2O3[2]. On the other hand, it was reported that aluminate glass had light transmitting ability between visible and infrared (IR) region[3]. It is expected that photocatalytic ability of iron-containing soda lime silicate glass might be increased by introduction of Al2O3 due to the high IR transmittance. In this study, we report a relationship between visible-light activated photocatalytic effect and structure of iron-containing soda lime aluminosilicate glass after isothermal heat treatment. 2. Experimental Iron-containing soda lime aluminosilicate glass with the composition of 15Na2O•15CaO•50Fe2O3• (20-x)SiO2•xAl2O3 (in mass%, x = 5~10 abbreviated as 50NCFSxA) was prepared by conventional melt-quenching method. Starting materials of Na2CO3, CaCO3, Fe2O3, SiO2 and Al(OH)3 were well mixed in an agate mortar. The mixture was poured into a platinum crucible and melted 1400 oC for 1 h. Glass samples were obtained by dipping the crucible bottom into ice cold water. The prepared glass was heat-treated at 1000 oC for 100 min. 57Fe-Mössbauer spectra (FeMS) were measured by using 57Co(Rh) and -Fe as a source and a reference, respectively. X-ray diffraction patterns were recorded between the 2of 10° and 80° with sampling range and scan speed of 0.02° and 5° min-1. Cu-K X-ray was generated by setting the voltage and current at 50 kV and 300 mA. Photocatalytic activity of heat-treated 50NCFSxA was evaluated by methylene blue (MB) decomposition test using 10 mL of 20 molL-1 MB aqueous solution and 40 mg of pulverized glass sample. Ultraviolet-visible light absorption spectra (UV-VIS) of MB after the decomposition test were recorded between 200 and 800 nm under irradiation of visible light with the ‘’ between 420 and 750 nm. 100 98 96 94 3. Results and discussion As shown in Fig.1, FeMS of heat-treated 50NCFS8A glass was composed of a paramagnetic doublet with the isomer shift () of 0.22 mm s-1, quadrupole splitting () of 0.79 mm s-1 and absorption area (A) of 47.2 %, and a relaxed sextet with  of 0.35 mm s-1, internal magnetic field (Hint) of 28.7 T and ‘A’ of 52.8 %, respectively. First order rate constant (k) for MB decomposition of heat-treated 50NCFS8A was estimated to be 1.81×10-2 min-1. In our previous study, the smaller ‘k’ of 4.78×10-4 min-1 was obtained for MB decomposition test using heat-treated 50NCFS0A glass, of which FeMS yielded a relaxed sextet with  Hint and ‘A’ of 0.34 mms-1, 37.9 T and 39.7 %, and a sextet with  Hint and ‘A’ of 0.36 mms-1, 51.8 T and 47.9 %, respectively[2]. These results indicate that the magnetic component observed in FeMS of heat-treated 50NCFS8A glass was smaller than that of 50NCFS0A glass. However,
photocatalytic activity of the former was much larger than that of the latter. It can be concluded that introduction of Al2O3 into iron-containing soda lime silicate glass increases the photocatalytic activity due to the enhancement of visible-infrared light transmittance. References [1] A. Fujishima, K. Honda, Nature, 238 (1972) 37-38. [2] S.Kubuki, et al., J. Radioanal. Nucl.Chem, 301 (2014) 1-7 [3] T.Nishida et al., J. Mater. Chem., 7(9), (1997) 1801-1806. 105
T10 CHARACTERIZATION OF AIR‐OXIDIZED NICKEL DOPED Li2FeSiO4 J.A. Jaén1, M. Castillo 106 Weeks2 1Depto. de Química Física, CITEN, Edificio de Laboratorios Científicos-VIP, Universidad de Panamá, Panamá 2Escuela de Química, Universidad de Panamá, Panamá *Corresponding author: e-mail: juan.jaen@up.ac.pa Keywords: Orthosilicates, Li2FeSiO4, air oxidation. Topic: T10- Physical Metallurgy and Materials Science The effect of ambient air exposure on Li2Fe1-xNixSiO4 (x=0, 0.10, 0.15, 0.20 and 0.3) has been investigated. This material belongs to a family of orthosilicates proposed as potentially cheap cathode materials for large-scale Li-ion batteries. Li2Fe1-xNixSiO4 samples were prepared by the solid-state reaction of Li2SiO3 with FeC2O4·2H2O and Ni(CH3COO)2·4H2O. They consist of crystals of monoclinic structure with (P21/n) symmetry, with some Fe3+ and/or magnetic impurities. Upon exposition to air for more than a year, FTIR results indicate that some amount of Li2CO3 was formed due to lithium removal from the original structure. Figure 1 shows the room temperature Mössbauer spectra of studied samples where it is evident the presence of Fe3+ with Mössbauer parameters QS ~ 0.68 mm/s and IS ~ 0.18 mm/s. These parameters are close to the reported values for fully delithiated LiFeSiO4 [1]. We thus attributed this doublet to partially delithiated orthosilicates Li2-yFe1-xNixSiO4 formed upon oxidation. The presence of Fe3+ negligible in most Mössbauer spectra of short-term air exposure (recently synthesized), is given in a separate contribution to this meeting. It is inferred that the adsorption of oxygen, carbon dioxide and other air components at the surface of the material upon air exposure provokes the lithium extraction leaving a delithiated particle. Segregated lithium form Li2CO3 at the particle surface. The oxidization of Li2Fe1-xNixSiO4 by air oxidation led to a surface change which is deleterious to the electrochemical performance of the cathode material. Figure 1. Room temperature Mössbauer spectra of air exposed Li2Fe1-xNixSiO4 samples for more than a year. References [1] A. Nytén, S. Kamali, L. Häggström, T. Gustafsson and J.O. Thomas, J. Mater. Chem. 16 (2006), 2266–2272.
T10 Fe‐DOPED DIOPSIDE (CaMgSi2O6) GLASS‐CERAMICS 107 P.S. Bayer1, M. Olzon- Dionysio2, M.J. M. Pires2, D. Olzon-Dionysio2, S. D. de Souza2, J. D. Fabris2, S. de Souza2, W. T. Shigeyosi3 and V.R. Mastelaro1 1 Instituto de Física de São Carlos - Universidade de São Paulo (USP), São Carlos, SP, Brazil 2Universidade Federal dos Vales de Jequitinhonha e Mucuri (UFVJM), Diamantina, MG, Brazil 3Departamento de Física, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil *Corresponding author: e-mail: maristolzon@hotmail.com Keywords: diopside, glass-ceramic, CaMgSi2O6 Topic: T10- Physical Metallurgy and Materials Science In more recent years, there has been an increasing interest in studying diopside-based ceramics and glass-ceramics, which present various important physical, chemical and biological properties. If it is used as a biomaterial, diopside is bioactive and may directly be bond to the human bone. Consequently, an important application is as dental and bone implant materials, among others, as nuclear waste immobilizers or for bone tissue engineering or even as sealing materials in solid oxide fuel cells. However, only the surface crystallization process occurs on the CaMgSi2O6 glassy sample, and to obtain the diopside material for such applications, the volume crystallization should be somehow promoted, as by using iron, titanium or zirconium oxides as doping agents, which allow obtaining glass-ceramic materials allowing them to be used in implants or dental prostheses. The main purpose of this research is to investigate the role of iron on the volume crystallization of CaMgSi2O6 doped with small amounts (2 – 9 mass%) of Fe2O3. The coordination environment and the oxidation state of iron are being investigated by Mössbauer spectroscopy, at room temperature. The hyperfine parameters (isomer shift; quadrupole splitting, and the relative subspectral areas for Fe2+ and Fe3+ doublets as a function of iron amount are presented in Figs. 1 and 2. It can be observed from Fig.1 that the proportion of Fe2+ is inversely proportional to the total amount of Fe2O3 until 7 mol%, to reach a plateau from then. Fig. 2 shows that isomer shift and quadrupole splitting values are nearly the same for all the samples. 1 2 3 4 5 6 7 8 9 10 80 70 60 50 40 30 20 Fraction (%) Fe2O3, wt% Fe2 Fe3 Figure 1. Fractions of the Fe2+ and Fe3+ doublets 1 2 3 4 5 6 7 8 9 10 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 Fe2O3, wt% mm/s iso2 iso3 Q2 Q3 Figure 2 Values of isomer shift and quadrupole splitting for the Fe2+ and Fe3+ doublets References [1] K. Otto, W. Wisniewski and C. Russel, Cryst. Eng. Comm15 (2013)6381
Acknowledgements: To Ms Alice Lopes Macedo, graduate student at UFVJM, for her kind help during the collection of Mössbauer data. This work supported by FAPESP and CNPq(Brazil). JDF is indebted to CAPES (Brazil) for granting his Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. 108
T10 MÖSSBAUER AND KINEMATICAL STUDIES OF MECHANOSYNTHESIZED NiFe2O4 H. Salazar1, C.A. Barrero1,*, 109 K.E. García1, M. Márquez2 1Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia, Medellín, Colombia. 2Grupo de Mineralogía Aplicada y Bioprocesos, Universidad Nacional de Colombia, Medellín, Colombia. *Corresponding author: E-mail: cbarrero@fisica.udea.edu.co Keywords: Ferrites; Mechanochemical processing; Kinematical modeling, Mössbauer spectrometry. Topic: T10 - Physical Metallurgy and Materials Science. Nickel ferrite, NiFe2O4, belongs to the spinel ferrite family of the MFe2O4 type, in which M is a divalent metal cation. The nanosized version of this family is interesting due to fundamental aspects related with nanomagnetism and also for their diverse potential applications [1]. Nanocrystalline NiFe2O4 has been prepared by several methods, including high energy mechanochemical route [1-3]. Due to the large number of variables involved in a given mechanochemical synthesis, there are many works that can be performed. In fact, by checking the experimental procedure of previously reported works, we notice that no two research groups have used similar machine conditions. Moreover, in none of these works, it is used a kinematical model of the planetary ball milling process to calculate the kinetic energy imparted by the balls to the starting reactants. The cumulative kinetic energy normalized to the powder mass (Ecum) could be a good criterion of comparison of all possible works, because it contains the values of all the machine variables [4]. We have carefully investigated the effect of some machine variables in the formation of NiFe2O4 when it is obtained via high-energy planetary ball milling of a stoichiometric mixture of NiO and α-Fe2O3, by combining both micro-structural and kinematical studies. Two sets of machine conditions, whose variables include angular speed of disc (), ball to powder mass ratio (mb:mp), number of balls (Nb), and duration of the milling (t), were explored. The products of the mechanosysnthesis were micro-structurally characterized by quantitative X-ray diffraction (XRD) using the Rietveld method and by 57Fe Mössbauer spectrometry (MS). For both set of machine conditions, as the milling time increased, the intensities of the Bragg peaks of NiO and hematite decreased differently, whereas those of the spinel phase increased. The production rate of NiFe2O4 by the first set of conditions was very low, however by using the second set and after 50 h of milling, 86 wt. % of this phase was formed. The MS of the samples generally consisted of sextets and doublets, the sextets were associated to micrometric- or nanometric-sized hematite and/or magnetically ordered nano-sized NiFe2O4, whereas the doublet was assigned to superparamagnetic nano-sized NiFe2O4. Finally, the energy transferred to the powders by the balls during milling in a planetary ball mill was calculated by using a kinematical model [5]. According to the model, Ecum of the order of 1,08 x109 J/kg was required to produce 86 wt. % of nickel ferrite when the second set of machine conditions for 50 h was employed. References [1] V. Šepelák, A. Düvel, M. Wilkening, K.-D. Becker and P. Heitjans, Chem. Soc. Rev. 42 (2013) 7507. [2] T.F. Marinca, I. Chicinas, O. Isnard, V. Popescu, J. Am. Ceram. Soc. 96 (2013) 469. [3] S. Bid, P. Sahu, S. Pradhan, Physica E 39 (2007) 175. [4] Gy. Kakuk, I. Zsoldos, A. Csanády and I. Oldal, Rev. Adv. Mater. Sci. 22 (2009) 21. [5] M. Abdellaoui and E. Gaffet, Acta Metall. Mater 43 (1995) 1087.
T10 MÖSSBAUER CHARACTERIZATION OF FEED COAL, ASH AND FLY ASH FROM A 110 THERMAL POWER PLANT Maricel Moreno 1, F. Reyes Caballero 1 and S. A. Martínez Ovalle 1 1Grupo de Física Nuclear Aplicada y Simulación, Facultad de Ciencias, Universidad Pedagógica y Tecnológica de Colombia. Tunja, Boyacá, Colombia. *Corresponding author: e-mail: maricel.morenol@uptc.edu.co Keywords: Feed coal, ash, fly ash, thermal power plant, Mössbauer spectroscopy Topic: T10- Physical Metallurgy and Materials Science 57Fe transmission Mössbauer spectroscopy has been used to characterize the iron-bearing minerals in feed coal, ash (up to 750 °C) and fly ashes from a thermal power plant in Boyacá, Colombia. The feed coal sample that was analyzed represents the bulk of coal being fed to the furnace of thermal power plant, Fig.(1). Various samples of high temperature ash (up to 750 °C) were prepared from feed coal. The fly ash was collected from a hopper of the electrostatic precipitator during the same period from feed coal collection, Fig.(2). Pyrite and an iron-containing aluminosilicate phase were the iron-bearing parent minerals observed in the representative sample of feed coal. The fundamental aim of the work was clarify the mechanism of conversion of iron-bearing minerals in feed coal through the process of combustion. -5 0 5 1,000 0,992 Backscattered (n.u) mm/s Figure 1. Mossbauer spectrum of feed Coal. The analysis of this and treated feed coal spectra was done while using spectra of low velocity. -10 0 10 1,00 0,99 0,98 Backscattered [n.u] mm/s Figure 2. Mossbauer spectrum of fly ash. The analysis of this was done while using spectra of low velocity. It can be seen in Fig. (2) the number of phases present in the feed coal remain in the fly ash, showing a change in the phases present initially in feed coal due to oxidation aluminosilicate phase, a magnetic phase appearing associated hematite. This phase transition undergone by the feed coal is exhibited when heated from 500°C so that the intensity ratio decreases proportionally. Discussion wider one arises from the detailed analysis of the Mossbauer parameters of the samples of heated of feed coal since evaluate of process of thermal power plant. References [1] F. Reyes, G. A. Perez Alcázar, J. M. Barraza, A. Bohórquez, J. A. Tabares and N. L. Speziali, Hyperfine Interactions. 148/149: 39-46, 2003. [2] F. Reyes, G. A. Perez Alcázar, J. M. Barraza, A. Bohórquez and J. A. Tabares, Hyperfine Interactions. 148/149: 31- 38, 2003.
T10 MÖSSBAUER SPECTROSCOPY ANALYSIS OF THE Ar‐51 METEORITE FROM THE 111 MUSEUM OF NATURAL HISTORY‐ LIMA, PERU Cerón Loayza M.L1*, Bravo Cabrejos J.A1. 1 Laboratorios de Análisis de Suelos y de Espectroscopia Mössbauer. Facultad de Ciencias Físicas. Universidad Nacional Mayor de San Marcos, Apartado 14-0149, Lima 14.Perú. *Corresponding author: e-mail: malucelo@hotmail.com Keywords: Meteorite, Ar-51, X-ray diffractometry, transmission Mössbauer spectroscopy. Topic: T10- Physical Metallurgy and Materials Science Mossbauer spectroscopy has proven to be a useful tool to study meteorite samples [1, 2], especially for this meteorite designated Ar-51 because it revealed rather different mineralogical phases. Ar-51 belongs to a collection of the Museum of Natural History of the Universidad Nacional Mayor de San Marcos, Lima, Peru; it was collected in the Region of Arequipa, about 900 km south of Lima; the exact site is unknown. The sample has a mass of about 1 kg; its surface is rough with reddish incrustations, probably caused by weathering. A piece of the sample was removed by cutting in order to proceed with the study of its phase composition using X-ray diffractometry (XRD) and 57Fe transmission Mössbauer spectroscopy (TMS); energy dispersive X-ray fluorescence (EDXRF) was used to study its elemental composition. In Figure 1 we can observe the results of the analysis of the content of structural phases by XRD; the following phases were found; albite (Al)-(Na,Al,Si3O8), augite (Au)-(Ca,Mg,Fe)2(Si,Al)2O6, pyroxene (Py), and clinopyroxene (Cly) (XY(Si,Al)2O6); the following metallic phase corresponding to the iron oxide magnetite (Mg)-(Fe3+)A (Fe22.5+)BO4 was also found. There is abundant albite and overlapping of the peaks belonging to the main phases Au, Al and Py; at 2= 35.75º we can observe the overlapping of the reflection peaks from Mg, Au y Py. The TMS spectra were taken at room temperature and high velocity. See Figure 2, where the following subspectra are observed: two paramagnetic doublets due to sites occupied by Fe2+, in the phases Py and Au; one doublet occupied by Fe3+ in another paramagnetic site assigned to Cly; and three magnetic sextets assigned to an oxidized magnetite (Fe3‐X O4): one of them has been assigned to the A‐tetrahedral sites occupied by Fe3+ with Bhf = 49.2 T, and the other two sextets to the B-octahedral sites with Bhf = 48.7 T and Bhf = 46.4 T, due to possible different directions of the hyperfine magnetic with respect to the principal axis of the crystalline electric field gradient. Figure 1. Diffractogram of the Ar-51 meteorite sample showing: albite (Al), pyroxene (Py), augite (Au), magnetite (Mg) and clinopyroxene (Cly) Figure 2. Mössbauer spectrum of the Ar-51 meteorite sample taken at room temperature (RT) Al – Albite Py – Pyroxene Au – Augite Mg – Magnetite Cly – Clinopyroxene 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 References 1800 1600 1400 1200 1000 800 600 400 200 0 AR-51 (Arequipa) Al Au Cly Py Au Mg Au Au Al Mg Py Au Py Au Py Py Al Cly Al Al Au Au Au Au Py Py Py Py Py Py Py Py Py Py Py Al Al Al Al Al Al Al Al Al Al Al Al Al Mg Mg Cly Cly Al 2 theta Intensity AR-51 -10 -5 0 5 1 0 1 .00 0 .99 Relative transmission (%) 0 .98 0 .97 0 .96 0 .95 Velocity (m m /s) [1] María L. Cerón Loayza et al. 2014. Hyperfine Interactions Volume 224, Combined 1-3, 143-152, DOI: 10.1007/s10751- 013-0866-x [2] María L. Cerón Loayza et al. 2011. Hyperfine Interactions Volume 203, Numbers 1-3, 17-23, DOI: 10.1007/s10751- 011-0365-x [3] Mössbauer Spectroscopy.Tutorial Book. Chapter 3.Application of Mössbauer Spectroscopyin Earth Sciences.Robert E. Vandenberghe and Eddy De Grave.
T10 MÖSSBAUER SPECTROSCOPY STUDY OF TWO CHONDRITE TYPE METEORITES María L. Cerón Loayza*, 112 Jorge A Bravo Cabrejos Laboratorio de Análisis de Suelos, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima 14, Perú. *Corresponding author: e-mail: malucelo@hotmail.com Keywords: chondrite meteorites, X-ray diffractometry, Mössbauer spectroscopy Topic: T10- Physical Metallurgy and Materials Science This work reports the results of the study of two chondrite meteorites. One of them impacted in an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima, and is classified as type IV chondrite. The second one impacted on 16 October 1975 in the state of Zacatecas, Mexico, and is classified as an ordinary LL5 chondrite; it has been denominated Tuxtuac. The physical characteristics of chondrite meteorites deserve special study in order to understand the formation and origin of the materials of extraterriastral origin that have been deposited in the Earth. There are previous studies of these two chondrite meteorites, such as the type IV from Carancas, which was recovered in situ [1,2] and the type LL5 Tuxtuac, whose magnetic properties have been studied in detail [3-5]. Hence, Mössbauer spectroscopy is a powerful tool to compare these two Chondrites found in the southern hemisphere of our planet and obtains more detailed information about metallic phases in this sample, using the 14.413 keV gamma ray nuclear transition in 57Fe. A conventional spectrometer was used with a sinusoidal velocity modulation signal and 1024 channels. The Mössbauer spectrum at room temperature (RT) of the sample was collected at the Laboratory of Archaeometry, Facultad de Ciencias Físicas, UNMSM. A 57Co source in a Rh matrix was used to collect the spectra, which were analyzed using the Normos program by Brand in its crystalline sites version and distribution of sites (Normos Site) [5]. The results show the presence of silicates such as olivine, pyroxenes and other sites of Fe+3; metallic phases such as taenite and opaque phases such as troilite. In figure 1(a) we can see the spectrum from Tuxtuac and in 1(b) we can see the spectrum taken from the magnetic portion extracted from this sample using a magnet; this information helped to define one of the metallic phases. (a) (b) Figure1. Mossbauer spectra of the chondrite meteorite Tuxtuac (a) the sample as found, and (b) only the magnetic fraction. Both spectra were taken at a velocity of 12 mm/s. References [1]María L. Cerón Loayza et al. 2014. Hyperfine Interactions Volume 224, Combined 1-3, 143-152, DOI: 10.1007/s10751-
013-0866-x [2]María L. Cerón Loayza et al. 2011. Hyperfine Interactions Volume 203, Numbers 1-3, 17-23, DOI: 10.1007/s10751-011- 0365-x [3]Atsuko Yamanaka et al. Proc. NIPR. Symp. Antarct. Meteorites, 8, 305-323. 1995. [4] Takesi Nagata et. Al. National Institute of Polar Research. 364-381. 1985. [4] A. L. Graham et.al. Meteoritics 23, 321 -323 (1988). [5] Brand, R.A., NORMOS: Mössbauer Fitting Program, 1995. 113
T10 STRUCTURAL, MORPHOLOGICAL AND MÖSSBAUER SPECTROSCOPY CHARACTERIZATION OF NANOSTRUCTURED TiFe0.5Ni0.5 Compound And Its Hydride 114 M. A. R. Martinez1, José André-Filho1, J. A. H. Coaquira1, L. L. Félix1, José Mestnik-Filho2 1Universidade de Brasília, Instituto de Física, Núcleo de Física Aplicada, Brasília, DF, CEP 70910-900. 2Instituto de Pesquisas energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, CEP 05508-000 *Corresponding author: e-mail: fisicorodriguez@gmail.com Keywords: intermetallic, ball milling, hydrogenation Topic: T10- Physical Metallurgy and Materials Science One way to improve the storage capacity of solid state matrices is to use intermetallic nanostructured materials. A high storage capacity is obtained with TiFe alloys (~1.9 wt%). The substitution of Fe by Ni can improve the activation of grains surface and reduce the equilibrium pressure of the hydride [1]. It is known that the presence of carbon clusters can improve the hydrogen absorption capacity of Ti-Fe-Ni nanostructured compounds [2]. In this work, we present the study of the structural, morphological and hyperfine properties of carbon-modified TiFe1-xNix (x=0.5) nanostructures and their hydrides. Bulk intermetallic matrices are prepared by a commercial arc-voltaic furnace and the carbon-modified nanostructured compounds are synthetized by using a ball milling equipment, under argon atmosphere. Hydrides compounds are obtained using the Sievert method with a high-purity hydrogen gas. The structural properties and crystallite sizes are determined by X-ray diffraction (XRD) technique. The hyperfine properties are characterized by Mössbauer spectroscopy and the morphological properties are studied by using Scanning electron microscopy (SEM). XRD data analysis indicates the formation of an intermetallic compound of single phase. Although, the milling process does not modify the crystalline phase, it drives to the broadening of the Bragg reflection peaks. That line broadening has been assigned to the crystallite size reduction and to the presence of residual strain. After the hydrogenation, it has been observed the formation of only the ∝ phase (hydrogen poor phase) for the unmilled sample. However, the coexistence of the ∝ and γ phases (hydrogen rich phase) has been determined for carbon-modified nanostructured sample. The analysis of the Mössbauer spectrum of the intermetallic TiFe0.5Ni0.5 alloy (bulk) obtained at room temperature (Fig.1a) is well-fitted with a singled whose isomer shift (IS) value is consistent with that one of TiFe alloy (within the uncertainty range). The Mössbauer spectra of the hydrogenated sample (Fig. 1b) were well-fitted with a singlet and a doublet which were associated with the  and β (a hydride phase) phases, respectively. No remarkable change was observed for the IS in the  phase, however, in the β phase, the IS showed a relative increase of +0.20 mm/s with respect to the alloy without hydrogen. This increase has been associated with a decrease in the “s” electron density at the Fe nucleus. On the other hand, the distortions produced by the hydrogen atoms provoke a crystalline phase transition from ∝ to β phase and it is manifested by the appearance of a nonzero quadrupole splitting (QS~0.21 mm/s). The Mössbauer spectra of the milled sample with carbon (Fig.1c) is well-resolved with a singlet and a sextet which correspond to the ∝ phase and metallic iron (likely arising from the milling vial set), respectively. For the carbon-milled sample (Fig. 1d), besides the singled and sextet, it has been determined the presence of a doublet with an IS of +0.36 mm/s [3] and a QS of 0.74 mm/s which was related to the γ phase in consistency with the XRD data. It suggests that the formation of the γ phase can be assigned to the presence of carbon which acts as a catalyst. Figure 1. Room temperature Mossbauer spectra of TiFe0.5Ni0.5 samples: bulk (a) and milled (c) and their hydrides (b) and (d), respectively.
References [1] Y. Liu, H. Pan, M. Gao, Q. Wang, J. Mater. Chem. 21, 4743 (2011) [2] E. M. B. Heller, A. M. Vredenberg, D. O. Boerma, Appl. Surf. Sci. 253, 771-777 (2006) [3] L J Swartzendrubert, L H Bennettt and R E Watson J. Phys. F: Metal Phys., 6, 12 (1976) 115
T10 SYNTHESIS OF A 300 TYPE STAINLESS STEEL BY MECHANICAL ALLOYING David Mena1, Jeferson 2000 1600 1200 800 116 Piamba Jimenez2, Modesto Fajardo3, German Antonio Pérez Alcázar2, Héctor Sánchez Shepa1 1Escuela de Ingeniería de Materiales Universidad del Valle. 2Departamento de Física Universidad del Valle. 3Departamento de Física Universidad del Cauca. *Corresponding author e-mail: hector.sanchez@correounivalle.edu.co key words: mechanical alloying, high energy ball mills, X ray diffraction, Mössbauer Spectrometry, stainless steel. Topic: T10- Physical Metallurgy and Materials Science The stainless steel type 300 is a set of austenitic steels readily for undergoing plastic deformation and they are used as containers because of their mechanical and corrosion resistance. We produced a composition: Cr 18%, Ni 9%, Mn 2 and the balance Fe, from technical pure powders utilizing a high energy ball mill.PM 400 Retsch®. A 1:20 mass powders to mass balls ratio was used and angular velocity of 300 rpm of the sun wheel. The milling was carried out under a vacuum of the order of 10-1mbars and The milling times were: 1, 4, 8, 12,15 18 hours. As the times elapsed, approximately 3gr of powder were taking off the anvils and an amount of balls just to maintain the stipulated mass powders to mass balls ratio. The evolution of the alloy was monitored by Mössbauer spectrometry and X ray diffraction. Each technique was fitted by the Rietveld method and Mosfit repectively, besides images from SEM were analized to assure the alloy was completed. 1,00 0,98 0,96 0,94 Hecho por Juan David Mena Guzman Hecho por Juan David Mena Guzman Experimental Teorico Singlete Distribucion Ajuste de los espectros mossbauer -9 -6 -3 0 3 6 9 Today's date is 03/03/2014 The Document name is: "UNTITLED.opj, A18HMENA#p" relative transmission V [mm/s] J.D.Mena 18 Horas 20 40 60 80 100 400 Intensidad (u.a) 2 Experimental Teorico Linea Base Diferencia FeNi NiMnCr Juan David Mena Guzman 18 Horas Hecho por Juan David Mena Guzman Mössbauer Spectrum, X ray diffraction and SEM image showing the alloy is consolidated. M.M.Rico, J.Sort, D.Baro, S.Suriñach, J.M.Greneche y G.A.PerezAlcazar–Análisis estructural de la serie Fe60Mn10Al30- XBX (2 ≤ X ≤ 10) preparada por aleamiento mecánico–Departamentos de Física de la universidad del Valle (Colombia), universidad de Barcelona (España) y universidad de Maine (Francia) - 2001.
Mössbauer Effect Reference and Data Journal August 2014 • Volume 37 • Number 6 Article and number are included under the authorization of Mössbauer Effect Reference and Data Journal. 117
118 Mössbauer Effect Reference and Data Journal Editors Tao Zhang Director Frank Berry, John Stevens Honorary Directors Junhu Wang Secretary General Changzi Jin, Xin Liu Research Associates Duorong (Lucy) Liu, Ya Ma Editorial Assistants Associate Editors AUSTRALIA P. de Souza BELGIUM Y. Garcia COLOMBIA C. A. Barrero JAPAN K. Nomura Y. Yoshida KOREA C. S. Kim RUSSIA I. S. Lyubutin Yu. D. Perfiliev V. G. Semenov USA E. E. Alp MEDC International Advisory Board AUSTRALIA S. J. Campbell – University of New South Wales AUSTRIA M. Reissner – Technische Universität Wien BELGIUM Y. Garcia –Université Catholique de Louvain BULGARIA I. Mitov – Institute of Catalysis, Bulgarian Academy of Sciences BRAZIL J. D. Fabris – Universidade Federal de Minas Gerais CHINA Y. F. Hsia – Nanjing University J. Y. Shen – Nanjing University FRANCE J.-C. Jumas – University of Montpellier II - Regional Mössbauer Platform J. -M. Grenèche - Université de Maine R. Rüffer – European Synchrotron Radiation Facility GERMANY F. E. Wagner – Technische Universität München H. Engelmann – Englemann Scientific Technologies HUNGARY E. Kuzmann – Eötvös Loránd University ITALY M. Carbucicchio – Università degli Studi di Parma JAPAN M. Takahashi – Toho University KOREA C. S. Kim – Kookmin University OMAN A. A. Yousif – Sultan Qaboos University RUSSIA S. M. Irkaev – Institute for Analytical Instrumentation, Russian Academy of Sciences M. Y. Silin – RITVERC GmbH SPAIN J. F. Marco – Instituto de Química-Física “Rocasolano” SWEDEN L. Häggström – Uppsala Universitet USA C. Wynter – Nassau Community College T. Kent – SEE. Co. The Mössbauer Effect Reference and Data Journal (MERDJ) is published ten times a year (each month excluding January and February) plus an Index Issue at the end of December by the Mössbauer Effect Data Center. Subscriptions: The annual subscription rate for Volume 37 (2014) is US$1,500.00 ($1,200.00 without the Index Issue). Subscription inquiries and address changes should be addressed to the General Manager at the address below. Mössbauer Effect Data Center Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road, Dalian 116023, China Tel: +86 411 8437 9159 Fax: +86 411 8468 5940 Email: medc@dicp.ac.cn Web: www.medc.dicp.ac.cn ISSN 0163-9587 On the cover: This issue, our front cover is graced by the memorial pictures of Professor José Domingos Fabris for continuously celebrating the 25th anniversary of the world largest regional Mössbauer community. See Editor’s Comments and the contents in the enclosed Mössbauer Spectroscopy Newsletter th
Mössbauer Effect Reference and Data Journal 119 August 2014 • Volume 37 • Number 6 Contents Contents ........................................................................................................................................................................... 129 Reference Listing............................................................................................................................................................. 131 Data Listing ..................................................................................................................................................................... 136 Subject Index ................................................................................................................................................................... 139 Mössbauer Newsletter ................................................................................................................................................... 141 Editor’s Comments The Latin America Community of Mössbauer spectroscopy was founded in 1982, and till 2013 it had been successfully operated 25 years. It is the largest regional Mössbauer community in the world and biennially organizes the local conference of LACAME (Latin American Conference on the Applications of Mössbauer Effect). It has been having a very close relationship with the MEDC for a long time, and now this close relationship was well maintained after the MEDC was relocated in Dalian. In 2010 and 2012, I and Professor Tao Zhang, the current director of MEDC, were invited to attend the LACAME conferences held in Lima and Medellin, respectively. Lima’s trip was very memorable for me as it was the longest flight (about 30 hours’ flight) in my life. For celebrating the 25th anniversary of the Latin America Community of Mössbauer spectroscopy, initiated by Professor Roberto Carlos Mercader from Argentina, I accepted Tao Zhang’s suggestion and started to organize our special issues of the MEDC data journal, MERDJ. I was fortunate enough that five of the most active Mössbauer scientists could kindly accept my invitation and submit their excellent contributions to the special issues. So it’s an extreme pleasure that our readers can enjoy the article from the founder of LACAME as well as the former vice chair of IBAME, Professor Elisa Baggio Saitovitch from Brazil. Last issue, we had officially kicked off the special issues for celebrating the Latin American Community of Mössbauer spectroscopy by sharing the celebration articles contributed by the representatives of seven Latin American countries, Professors’ Elisa Baggio Saitovitch and Roberto Carlos Mercader. This issue, we continue the celebration by publishing Professor José Domingos Fabris’s contribution. The details, please read the enclosed Mössbauer spectroscopy newsletter. Junhu Wang Secretary General and Editor
is pleased to offer these publications and services to the international Mössbauer community... The Journal reports as thoroughly as possible all published information on Mössbauer spectroscopy. An annual subscription includes ten issues plus an index issue. Each issue includes a Reference Listing, a Data Listing, an Abbreviation Listing, an Isotope Index, a Subject Index, and the Mössbauer Spectroscopy Newsletter. Mössbauer Web Sites ON THE WORLD WIDE WEB The Mössbauer Effect Data Center developed and administers two separate Web sites for the Mössbauer community (<www.mossbauer.org> and <www.medc.dicp.ac.cn> These sites provide Mössbauer researchers with pertinent and timely information, free of charge. Included on the sites are general information pertinent to the Mössbauer community, news items, regional lab information, position postings, information on upcoming conferences, the most recent Mössbauer Spectroscopy Newsletter, IBAME information, an E-Mail and Fax Directory of Mössbauer Authors, links to Mössbauer instrument and source suppliers, and further information regarding the Center's products and services. Access to the MEDC Web-Access Database is also provided through the MEDC site. Researchers may now access and search the MEDC database from their computers via the MEDC Web site. The MEDC Database contains both a Reference and a Data file, and includes search, sort, and print functions. For further information about these and our many other publications and services for the Mössbauer community, please visit us at our Web site Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road, Dalian 116023, China Phone: +86-411-84379159 Fax: +86-411-84685940 Email: medc@dicp.ac.cn Web: www.medc.dicp.ac.cn www.mossbauer.org 120
121 Trends and challenges of the Latin American Mössbauer community: a brief overview José Domingos Fabris Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), PRPPG, Campus JK, 39100-00 Diamantina, Minas Gerais, Brazil, and Department of Chemistry - ICEx, Federal University of Minas Gerais (UFMG), 31270- 901 Belo Horizonte, Minas Gerais, Brazil. Email: jdfabris@ufmg.br Abstract T he m a p of t h e nu m be r of Mö ssb a ue r spectroscopy publications worldwide has changed in different regimes of evolution over the three last decades. The main tendencies were reportedly systematized by broadly grouping them according to countries of the institutional affiliations of their authors. In Latin America, four countries - Argentina, Brazil, Colombia and Mexico – were responsible for ~3.7% of the global articles published be twee n 1958 a nd 2009 a nd ~93% of t he articles on Mössbauer spectroscopy of all Latin American authors between 1958 and 2009. For these four countries, certainly as an image of a much broader regional trend, the research activity has been constantly increasing since the 1980s. This trend emphasizes the role of the Latin American Conference on the Applications of the Mössbauer Effect in this regional performance over the last twenty five years and of its strategic importance in broadening the Mössbauer spectroscopy culture for future generations of researchers. It boosts connections to their scientific works and opens new opportunities to address developments following new technological demands, particularly those with more regional appeals. The cited scientific references in this text come essentially from a personal selection to merely sustain the arguments to stimulate multilateral scientific integrations, in part based on my self- August 2014 experience, but they do not intend to represent in any completeness the ample scientific world involving Mössbauer spectroscopy in Latin America. José Domingos Fabris: Doctor in Science – Chemistry (1977) at the Federal University of Minas Gerais (UFMG), Brazil; Post-Doctoral at the Centre d'Études Nucléaires de Grenoble (1978), France, and at the Department of Crystallography, Birkbeck College, London Uni ve rsi t y (1991), E ngl a nd; L e c t ure r of Che m i st ry (1971 – 1986) a t t he Fe de ra l University of Viçosa, Brazil; Senior Researcher (1986 – 1997) at the Brazilian Agriculture Research Organization - EMBRA PA; Full Professor of Chemistry (UFMG, 1997 - 2010; currently, retired); CAPES (Brazil)/Fulbright (USA) Senior Visiti ng R e searche r (March – June 2006) at the University of Illinois at Urbana-Champaign, USA; Visiting Professor (PVNS/CAPES program, from 2010 to present) at the Federal University of the Jequitinhonha and Mucuri Valleys, Brazil. A list of scientific publications may be found on the curriculum vitae (in Portuguese) at the web address http:// lattes.cnpq.br/8091857216878149.
122 1. Introduction Born from the elegant physical arguments used to explain experimental results of the resonant absorption of gamma radiation involving recoilless atomic nuclei, the Mössbauer effect was formally described and first reported by its discoverer, Rudolf Ludwig Mö ssb a u e r, i n 1 9 5 8 [ 1 , 2 ] . T h e r e su l t a n t Mössbauer spectroscopy was first used for studies of problems on the physics and chemistry of solids and progressively expanded to other topics on a wider range of the more recent scientific and technological fields. During the fifty years from 1958 to 2009, more than 70,000 Mössbauer spectroscopy articles were published [3]. If calculated per year, the maximum number of annual publications was reached during the 1990s and declined globally since (Figure 1). But [4]. Figure 1. Mössbauer spectroscopy publications per year (1958 - 2009); data obtained from refs. [3] and the profile of the publications is distinguishable according to the group of countries. The first group of histograms in Figure 2, corresponding to data for China, France, Germany and Japan, represents countries that responded for about 29% of all Mössbauer spectroscopy articles from 1958 to 2009, and for which the related research activity followed the general increasing trend from the 1980s to the 1990s, followed by a decrease in the 2000s. The second group of histograms, for Canada, England, India, Russia and the USA (~33% of all articles between 1958 and 2009), represents countries in which activity has been decreasing for the last two decades relative to that of the 1980s. Finally, for the group of countries encompassing the Czech Republic, Oman and Pakistan (~0.3% of all articles between 1958 and 2009), along with the four Latin American countries ― Argentina, Brazil, Colombia and Mexico – who are responsible for ~3.7% of the global articles between 1958 and 2009 and ~93% of all the articles on Mössbauer spectroscopy from Latin American authors between 1958 and 2009. For these four Latin American countries, the research activity has been constantly increasing since the 1980s. According to the data of [3], the number of Mössbauer spectroscopy publications by all Latin American authors between 1958 and 2009 represented about 4% of all the corresponding articles published worldwide. 2. What might those data mean? The identification of the main reasons governing these trends is not an easy or fully reliable task. The inspection of histograms in ref. [4] reveals that some Mössbauer topics (e.g., synchrotron Mössbauer, superconductivity, magnetism, exotic isotopes, spin crossover effects w ith phas e trans itions ) have been historically dominant and reached a maximum number of global publications during the 1990s
Figure 2. The dynamics of the number of publications on Mössbauer spectroscopy over three decades (1980s, 1990s and 2000), as represented by the three sequential bars, per geographic region [4]. The first group of charts (brown) represents areas in which activity followed the general trend of increase from the 1980s to 1990s, and then a decrease in the 2000s. The second group of charts (red) represents areas in which activity has been decreasing for three decades. The final group of charts (green) represents areas in which activity has been constantly increasing since the 1980s. (in the case of nanoparticles, during the 2000s), but decreased slightly since then. Moreover, a comparison of the data for 2008 with that of 2000 indicates that research activities worldwide related to oxides, metals, alloys and minerals have evolved [5] (Figure 4). The increase in scientific topics corresponds to what can be broadly interpreted as being the preferred area of Mössbauer research in Latin American laboratories (Figure 5): oxides and corrosion, alloys and, remarkably, mineralogy. The main research activities correlated with the number of laboratories [6] (Figure 5) appear in the following order: mineralogy > alloys > corrosion ≈ nanotechnology. However, Latin American Mössbauer researchers have also been done significant work on magnetism, medical technologies, environmental problems, archaeometry and theoretical/fundamental physics. 123 An analytical focus on the scientific
124 competence of individual researchers and on the physical facilities found in many Latin American Mössbauer laboratories evidences their capability to solve problems related to the assessment in deeper knowledge of the natural resources, of the cultural meaning of materials and their historical artifacts, the preservation or remediation of polluted areas in their natural environment and the rational use of the mineral richness for technological purposes in the countries of the region. This understanding has been, in part, stimulating collective efforts of the regional Mössbauer community to become integrated by sharing their laboratory facilities, opening opportunities for the exchange of students and researchers among countries, and by promoting regional scientific meetings. The integration has culminated in the advent of the biennial Latin American Conference on the Applications of the Mössbauer Effect (LACAME) twenty-five years ago and has been
Figure 3. Distribution of publications on Mössbauer spectroscopy per Latin American country between 125 1958 and 2009 (based on data from ref. [3]) Figure 4. Number of publications per selected topic in 2000 and 2008 (based on data from ref. [4]).
Figure 5. Some general Mössbauer topics being dealt with by Latin American Mössbauer groups. Frequency values on the ordinate axis were deductively drawn from refs. [5] and [6]. rendering significant practical results. 126 A few and sparsely chosen scientific studies of our groups at the UFMG and at the UFVJM that have been done in collaborations with colleagues in Brazil and in neighboring countries (mainly in Argentina, Chile, Colombia and Peru) may be broadly grouped according to some scientific or technological interests. In Brazil, collaborators have been more often of the Brazilian Center of Physical Research (CBPF), in Rio de Janeiro; the Center for the Development of the Nuclear Technology (CDTN), in Belo Horizonte, Minas Gerais; the State University of Maringá (UEM), in Paraná; the Federal University of Espírito Santo (UFES), the Federal University of Ouro Preto (UFOP), in Minas Gerais, and the Federal University of Pi a uí (UFPI). In ot he r L a t i n Am e ri c a n countries, mainly of the National University of La Plata (UNLP), Argentina; the University of Santiago (USACH), Chile; the Pedagogical and Technological University of Colombia (UPTC), in Tunja, Colombia and the University of San Marcos (UNMSM), Peru. 3. Specific topics 3.1. Mineralogy Taking into account only selected cases related to the various geological systems in the Latin America, tropical and sub-tropical soils [7, 8] and sediments [9] in Brazil and volcanic geomaterials from Chile [10] are commonly rich in iron-bearing minerals, some of which are magnetic. Understanding their chemical, physical and mineralogical properties has also been a fundamental concern in the perspective of using them for technological purposes, such as adsorbents or catalysts for environmental remediation or energy production. Systematic collaborative studies involving researchers at the UFMG, USACH and UFVJM have been devoted to the mineralogy of magnetic iron oxides in volcanic soils from Chile in advanced oxidation processes (AOP; specifically, the Fenton reaction) for environmental remediation (e.g., [11, 12]) and the water gas shift gas reaction [13] to produce hydrogen from carbon monoxide and water. Moreover, other minerals, more specifically zeolites and imogolite from those volcanic geomaterials from Chile, were found to form interesting magnetic composites with magnetite, which has a high adsorptive ability, to remove anions from contaminated water in environmental remediation of areas affected by mining activities [14-16]. In antiquity, human groups also used minerals for rupestrian paintings and the production of (now) archaeological ceramics.
127 Long-term joint studies by researchers and undergraduate and graduate students at the CBPF, CDTN, UFMG, UFPI and UFVJM have successfully identified iron oxides of archaeological ceramics [17] and pigments of rupestrian paintings [18, 19] in Brazil. Pigment materials from rupestrian paintings c a nnot a rbi t ra ri l y be obt a i ned by di re c t l y removing them from rock walls in protected archaeological sites or from fragments of archaeological pieces. Mainly for this reason, Mössbauer non-destructive measurements must be performed in s itu . The U FP I has recently acquired a backscattering MIMOS II Mössbauer setup [20] to be specially used for archaeological studies. 3.2. Pedology: iron in organic soils Iron has been considered a pedogenic marker to help trace pedogenetic mechanisms in organic soils. For the first time, 57Fe Mössbauer measurements in samples of peat mires from two sites of the upper Jequitinhonha Valley, Brazil, were recently performed by researchers from the UEM, UFVJM and UNLP [21, 22]. 3.3. Iron ore mines and industrial beneficiation of kaolin Mössbauer spectroscopy has also been the key tool in assessing the iron mineralogy of geomaterials from nickel [23] and coal [24, 25] mines in Colombia, and manganese, in Brazil [26], and in tracking chemical changes induced by industrial processing of kaolin from mines in Brazil [27-29]. 3.4. Synthetic iron oxides P u r e i r o n o x i d e s o r i r o n o x i d e s isomorphically-doped with foreign cations for use as heterogeneous catalysts for advanced oxidation [30] have been synthesized at the UFMG. They are to be used to clean natural water bodies contaminated with or ganic pollutants and for photocatalysis, to promote the molecular splitting of water and produce gaseous molecular hydrogen [31]. Nanosized magnetic iron oxides forming ferrofluids have been assayed at the CDTN, UFES, UFMG, UFOP and UFVJM in attempts to assess their structural (crystallographic, magnetic, and hyperfine) properties and obtain experimental data regarding the potentiality of their use in advanced technologies for medical diagnosis and therapy (hyperthermy and magnetically-o ri e nt e d d ru g de l i v e ry ) i n o nc o l o g y [ 32 ] (reviews also covering aspects of those studies are in refs [33-35]). 4. Concluding remarks The Mössbauer communi ty in Lat in American is experiencing an increase in scientific activities, considering the number of publications; the number of active Mössbauer laboratories, such as the new setup at USACH, Chile, and their capability is also expanding, although laboratories are still more concentrated in Argentina, Brazil and Colombia. National meetings (for instance, the biennial Jacques Danon Meeting on Mössbauer spectroscopy in Brazil) and the regional Latin American Conference on the Applications of the Mössbauer (LACAME) have been boosting the exchange of students and researchers in and among the countries of Latin America and the Caribbean, geographically covering a significant proportion of the American continent. LACAME has been playing a master role by creating the proper forum to integrate joint actions of more individual scientific teams for the past twenty-five years. Although many similar and more extensive examples than the multilateral collaborative works cited above can be found that also involve Brazilian and other researchers of institutions in Latin American countries, quite certainly, most of these integrating initiatives have emerged from the scientific atmosphere at the LACAME meetings. It must also be remarked that, despite the fact that more sophisticated physical facilities a nd o t he r r e sour c e s, i nc l u di n g e xp e rt i se , can be optimized and shared, particularly by geographically closer laboratories, there are a few immediate, unavoidable challenges in the horizon for the future of Mössbauer spectroscopy in Latin America: i. Suppl y, handl ing a nd t ransport of Mössbauer radioactive sources. ii. Maintain and improve academic and scientific exchange of students dealing with Mössbauer spectroscopy throughout the Latin American countries. The national supporting agencies may act by more intensely “catalyzing” those actions. iii. National and regional Mössbauer meetings might be more highly focused on major “hot topics”, which would be chosen for each meeting, while keeping them unrestrainedly free and open for all scientific contributions. iv. Would a multinational laboratory to provide the most sophisticated and usually expensive facilities (very low temperature, magnetic field, special Mössbauer sources…)
128 be a reasonable alternative to complement the current individual laboratory facilities in Latin America; v. Mössba ue r sync hrot ron. Can t he Brazilian National Laboratory of Synchrotron Light provide the radiation beam-line and host the corresponding Mössbauer setup? At least some of these few points may become recommended items for fruitful discussion by the Latin American Mössbauer community and at the LACAME forum. 5. Acknowledgments The author is indebted to CAPES (Brazil) for granting his Visiting Professorship at the UFVJM under the PVNS program and t o the FAPEMIG and CNPq (currently, grant # 305755-2013-7; Brazil) for having supported many of the Mössbauer laboratory activities at the UFMG and UFVJM; also to my colleagues David Lee Nelson, Enver Murad and Luis Carlos Duarte Cavalcante for their helpful comments on the manuscript. The scientific interest and research activities of this author on the physics of iron-bearing minerals were also built up and markedly strengthened all along the more than two decades of scientific cooperation, from the beginning of the 1980s, with Professor John Michael David Coey, Department of Physics, Dublin University, Ireland. 6. References [1] R. L. Mössbauer: Kernresonanzfluoreszenz von Gammastrahlung in Ir-191, Zeitschrift für Physik 1958, 151(2), 124. [2] R. L. Mössbauer: Kernresonanzabsorption von Gammastrahlung in Ir. Zeitschrift für Naturforschung. Part A-Astrophysik Physik und Physikalische Chemie 1959, 14(3), 211. [3] The Mössbauer Effect Data Center: Total Number of Publications per Country 1958-2009 , Mössbauer Effect Reference and Data Journal 2009, 32(5), 72. [4] Stevens, J. G.: The Future of the Mössbauer Effect Data Center Conference. Talk at the opening ceremony of MEDC relocated in Dalian, China, in July 2010. [5] The Mössbauer Effect Data Center: The Latin American Mössbauer Community, Mössbauer Effect Reference and Data Journal 2004, 27(7), 183. [6] The Mössbauer Ef fect Data Center: Mössbauer Spectroscopy in Latin America, Mössbauer Spectroscopy Newsletter October 2008. [7] J. D. Fabris, J. M. D. Coey, W. N. Mussel: Magnetic Soils from Mafic Lithodomains in Brazil, Hyperfine Interactions 1998, 113, 249. [8] J. H. M. Viana, P. R. C. C Couceiro, J. D. Fabris, E. E. Fernandes Filho, C. E. G. R. Schaefer, H. R. Rechenberg, W. A. P. Abrahão, E. C. Mantovani: Occurrence of Magnetite and its Transformation to Hematite in the Sand Fraction of a Brazilian Oxisol, Australian Journal of Soil Research 2006, 44(1), 71. [9] G. T. Aragon, F. L. Silva, D. A. Bustamante, R. B. Scorzelli, J. D. Fabris: Chemical Dynamics of Fe Compounds in Brazillan Mangrove Sediments Studied by Mössbauer Spectroscopy, In: M. F. T hom a s, J. M. Wi l l i a m s, T. C. Gi bb. (Orgs.). Hyperfine Interactions (C) 2002, 1ed. Dordrecht, Kluwer Academic Publishers, 5, 387. [10] A. C. Silva, M. Escudey, J. E. Förster, C. Pizarro, J. D. Ardisson, U. M. Barral, M. C. Pereira, J. D. Fabris: Iron-bearing Minerals in Ashes Emanated from Osorno Volcano, in Chile, Hyperfine Interactions 2014, 224, 153. [11] V. Manzo, C. Pizarro, M. A. Rubio, L. C. D. Cavalcante,V. K. Garg, J. D. Fabris: Preparative Treatment With NaOH to Selectively Concentrate Iron Oxides of a Chilean Volcanic Soil Material to Produce Effective Heterogeneous Fenton Catalyst, Hyperfine Interactions 2011, 203, 59. [12] S. Aravena, C. Pizarro, M. A. Rubio, L. C. D. Cavalcante, V. K. Garg, M. C. Pereira, J. D. Fabris, J.D.: Magnetic Minerals from Volcanic Ultisols as Heterogeneous Fenton Catalysts, Hyperfine Interactions 2010, 195, 35. [13] C. Pizarro, M. Escudey, S. A. Moya, J. D. Fabris: Iron Oxides From Volcanic Soils as Potential Catalysts in The Water Gas Shift Reaction, In: M. Garcia, J. F. Marco, F. Plazaola (Orgs.), Industrial Applications of the Mössbauer Effect - International Symposium on the Industrial Applications of the Mössbauer Effect. American Institute of Physics - AIP Conference Proceedings 2005, 765, 56. [14] M. Gutierrez, M. Escudey, J. Escrig, J. C. Denardin, D. Altbir, J. D. Fabris, L. C. D. Cavalcante, M. T. García-Gonzalez: Preparation and Characterization of Magnetic Composites Based on a Natural Zeolite, Clays and Clay Minerals 2010, 58(5), 589–595. [15] N. Arancibia-Miranda, M. Escudey, C. Pizarro, J. C. Denardin, M. T. García-González, J. D. Fabris, L. Charlet: Preparation And Characterization Of A Single-Walled Aluminosilicate Nanotube- Iron Oxide Composite: Its Applications to Removal of Aqueous Arsenate, Materials Research Bulletin 2014, 51, 145. [16] L. C. A. Oliveira, R. V. R. A. Rios, K. Sapag, J. D. Fabris, R. M. Lago: Magnetic Particle Technology: A Simple Preparation of Magnetic Composites for the Adsorption of Contaminants in Water, Journal of Chemical Education 2004, 81(2), 248. [17] D. L. Floresta, J. D. Ardisson, M. Fagundes, J. D. Fabris, W. A. A. Macedo: Oxidation States of Iron As An Indicator of the Techniques Used to Burn Clays and Handcraft Archaeological Tupiguarani Ceramics By Ancient Human Groups In Minas
129 Gerais, Brazil, Hyperfine Interactions 2013, 224, 121. [18] L. C. D. Cavalcante, M. F. Luz, N. Guidon, J. D. Fabris, J. D. Ardisson: Ochres From Rituals of Prehistoric Human Funerals at The Toca do Enoque Site, Piauí, Brazil, Hyperfine Interactions 2011, 203, 39. [19] T. L. Alves, M. A. M. L. Brito, M. C. S. M. Lage, L. C. D. Cavalcante, J. D. Fabris: Pigmentos de Pinturas Rupestres Pré-Históricas do Sítio Letreiro do Quinto, Pedro II, Piauí, Brasil, Química Nova 2011, 34, 181. In Portuguese. [20] G. Klingelhöfer, G. B. Bernhardt, J. Foh, U. Bonnes, D. Rodionov, P. A. Souza, C. H. Schröder, R. Gellert, S. Kane, P. Gütlich, E. Kankeleit: The Miniaturized Mössbauer Spectrometer MIMOS II for Extraterrestrial and Outdoor Terrestrial Applications: A Status Report, Hyperfine Interactions 2002, 144/145, 371. [21] R. C. Me rc ade r, A. C. Si l va, M. L . Montes, F. R. Sives, A. Paesano Jr, J. D. Fabris: Chemical Fate of Iron in a Peatland Developing in the Southern Espinhaço Chain, Brazil, Hyperfine Interactions 2014, 226, 509. [22] A. Paesano Jr, A. C. Silva, F. F. Ivashita, C. F. Cerqueira, F. Sives, R. C. Mercader, J. D. Fabris: Chemical Reducing Pedoenvironment in A Peatland Influenced by Hematitic Phyllite Lithology in The Southern Espinhaço Chain, Brazil, Hyperfine Interactions 2014, 226, 585. [23] J. D. Fabris, C. M. Gonçalves, W. A. P. Serrano: Chemical and Mineralogical Analyses of a Weathering Mantle Developing on Peridotite of the Mining Area For Nickel in Cerro Matoso, Colombia, Hyperfine Interactions 1999, 122, 171. [24] W. A. Pacheco Serrano, D. Q. Lima, J. D. Fabris: Mössbauer Analysis of Coal Coke Samples from Sa m a c á , Boya c á , Col om bi a , Hy pe rf i ne Interactions 2013, 224, 271. [25] W. A. Pacheco Serrano, D. Q. Lima, J. D. Fabris: Mössbauer Analysis of Coal Coke Samples from Sa m a c á , Boya c á , Col om bi a , Hy pe rf i ne Interactions 2014, 224, 277. [26] C. K. Nascimento, M. C. Pereira, L. C. D. Cavalcante, A. M. Lana, E. Murad, J. P. Braga, J. D. Fabris: Hyperfine Structure of 57Fe in Minerals from a Manganese Ore Deposit, Hyperfine Interactions 2011, 203, 25. [27] P. G. Pinheiro, J. D. Fabris, W. N. Mussel, E. Murad, R. B. Scorzelli, V. K. Garg: Beneficiation of a Commercial Kaolin from Mar de Espanha, Minas, Gerais, Brazil: Chemistry and mineralogy, Journal of South American Earth Sciences 2005, 20(3), 267. [28] E. Murad, J. D. Fabris: Kaolin Mining and Beneficiation: the Role of Iron. Journal of Physics - Conference Series (Online) 2010, 217, 012066. [29] W. D. Mussel, E. Murad, P. S. R. Criscuolo, P. G. Pinheiro, J. D. Fabris: Variation of Mineralogy During the Beneficiation of Capim Kaolin from Pará, Brazil, Clay Minerals 2008, 43, 381. [30] D. Q. L. Oliveira, L. C. A. Oliveira, E. Murad, J. D. Fabris, A. C. Silva, L. M. Menezes: Niobian Iron Oxides as Heterogeneous Fenton Catalysts for Environmental Remediation, Hyperfine Interactions 2010, 195, 27. [31] M. C. Pereira, E. M. Garcia, A. C. Silva, E. Lorençon, J. D. Ardisson, E. Murad, J. D. Fabris, T. Matencio, T. Castro Ramalho, M. V. J. Rocha: Nanostructured -FeOOH: A Novel Photocatalyst for Water Splitting, Journal of Materials Chemistry 2011, 21, 10280. [32] P. Chagas, A. D. Silva, E. C. Passamani, J. D. Ardisson, L. C. A. O. Oliveira, J. D. Fabris, R. M. Paniago, D. S. Monteiro, M. C. Pereira: δ-FeOOH: A Superparamagnetic Material for Controlled Heat Release Under AC Magnetic Field. Journal of Nanoparticle Research 2013, 15, 1544. [33] A. L. Andrade, R. Z. Domingues, J. D. Fabris, A. M. Goes: Safety of Magnetic Iron Oxide- Coated Nanoparticles in Clinical Diagnostics And Therapy, In: H. A. Khan, I A. A. (Org.), 2012, Toxic Effects of Nanomaterials, 1ed Oak Park, Bentham Science Publishers 2012, 67. [34] R. V. Ferreira, J. D. Fabris, R. Z. Domingues: Magnetic Hyperthermia Studies in Magnetite Ferrofluids, In: D. M. Angrove (Org.), Magnetite: structure, properties and applications, New York, Nova Publishers 2011, 379. [35] A. L. Andrade, R. Z. Domingues, J. D. Fabris, A. M. Goes: Safety of Magnetic Iron Oxide- Coated Nanoparticles in Clinical Diagnostics and Therapy, In: H. A. Khan, I. A. Arif (Org.), Toxic E ffe c t s of Na nom a t e ri a l s 2012. 1 e d Oa k Pa rk, Bentham Science Publishers, 67.
130 LACAME 2014, MEXICO Dear Mössbauer Community: The XIVth Latin American Conference on the Applications of the Mössbauer Effect – “LACAME 2014” will take place at the UAEM DECA in Toluca City in the State of Mexico, Mexico from November 10th to 14th, 2014. Toluca is a city located at more than 2600 m above sea level and at 70 km from Mexico City (around 1 hour by bus). The modern and constantly evolving industrialized Toluca City has been able to preserve the great cultural, artistic and natural heritage in its zone, which is characterized by the artistic genius of its people and the richness of its valleys. Its ancient history takes us to the Matlatzincas, who left their imprint in the archaeological zone of Calixtlahuaca. In the historical City Center one can still breathe the Colony period, when walking through the narrow alleys and big houses made of covered mud that take us to the Portals, where traditional candies and street concerts fill the air. There, the impressive architecture of the Cathedral, with its Roman reminiscences, the Merced Church and the Santa Veracruz Parish can be appreciated. Toluca's climate is the coolest of any large Mexican city due to its altitude, winter nights are cold and the temperature may drop below 0 °C (32 °F). Throughout the year, the temperature is rarely below −3 °C (27 °F) or above 27 °C (81 °F). LACAME (Latin American Conference on Applications of Mössbuer Effect) is a series of scientific events that take place every two years in some Latin American Country. This year, Mexico has been selected to host the 14th Conference on the applications of the Mössbuer Effect. This event not only stimulates the development of the Mössbuer spectroscopy but also offers a perfect frame for high level discussions. This Conference will offer both the Mexican and Latin American communities the opportunity of interacting with first class international researchers talking about different interesting topics. The Mössbuer spectroscopy is a suitable and powerful technique for very specific studies. Indeed, some of the great advantages featured by this technique are that in spite of its relatively low cost, it provides insightful results for advanced research studies and it can be applied in a variety of scientific and industrial fields.
131 Invited Speakers E. M. Baggio Saitovitch – CBPF Brazil Magnetism and superconductivity studies on doped BaFe2As2 single crystals seen by Mössbauer Spectroscopy. R.C. Mercader – UNLP Argentina Design of self and matrix supported systems of iron oxide nanoparticles for catalytic applications. C. A. Barrero - Universidad de Antioquia, Colombia Contributions of Mössbauer spectrometry t o t h e st u d y o f so me d i l u t e d ma g n e t i c semiconductor oxides: A critical review J. A. Jaen - Universidad de Panamá Structural, electrical and magnetic study on Li2Fe1-xNixSiO4 cathode material for lithium-ion batteries T h e O r g a n i z i n g C ommi t t e e o f LACAME-2014 is also planning some video conferences. The abstracts will be published in a meeting abstract book. Selected contributions will be considered for publication in a special issue of Hyperfine Interactions. Peer review with strict refereeing standards will be applied. Dates 20 June, 2014: Final announcement. 28 June, 2014: Deadline for abstracts. 10 A u gu st, 2014: N otification for the acceptance. 10 September, 2014: Deadline for earlier registration. 1 2 No v e m be r, 2 0 1 4 : De a d l i n e f o r a l l manuscripts. 10 - 14 November, 2014: LACAME 2014, México. Mex i can Gr oups with Mössbauer Laboratories I n st i t u t o Na c i o n a l d e I n v e st i g a c i o n e s Nucleares, ININ (National Institute of Nuclear Research). State of Mexico. Universidad Nacional Autónoma de México, UNAM (National Autonomous University of Mexico). Mexico City. Instituto Politécnico Nacional, IPN, (National Polytechnic Institute). Mexico City. Instituto Mexicano del Petroleo, IMP (Mexican Petroleum Institute). Mexico City Mössbauer Spectroscopy Topics devoted of Mexican groups are: (1) magnetic materials, 2) structural properties of iron based alloys 3) study of thin films of 57Fe by Mössbauer spectroscopy, DCEMS. However
132 most of them have been devoted to two main areas: corrosion and heterogeneous catalysis. In the last years these groups have been working to evaluate the corrosion produced in pipelines transporting crude and refined oil in the Mexican petroleum industry, which is one of the biggest in the world. These corrosion products have been obtained from sludge get from the pipeline cleaning with smart pigs or from a steel coupon exposed in an industrial environment. Concerning to heterogeneous catalysis; Mössbauer Spectroscopy has been used for applications in the oil refining and petrochemical industry. In relation to non-supported mixed oxide catalysts, one of these groups has came working on Fe-Zn-O and Fe-Zn-Cr-O mixed oxide materials applied to oxidative dehydrogenation of n-butane and 1-butene to butadiene. The Mössbauer spectroscopy technique has been used to elucidate the nature of active sites presents on bulk mixed oxides as well as the cooperative effect of different phas es present in the solids on its catalytic behavior. T h e i nc or p o ra t i o n of c h r om i u m i nt o z i n c ferrite catalyst greatly increases butadiene and CO 2 selectivity in n-butane oxidative dehydrogenation. The chromium incorporated into octahedral sites in the spinel structure seems to increase the basicity of the lattice oxygen. More basic oxygen seems to promote the acid-base type dissociation of the C-H bond during butane/butene activation to produce butadiene. In this same sense, in order to increase the exposed area of bulk mixed oxides, these materials were supported on silica and alumina. The Mössbauer spectroscopy technique has been used to show the effect of support on the electronic properties of active sites, presents on bulk mixed oxides, on its catalytic behavior. The IMP Mössbauer Spectroscopy group has applied with success this spectroscopy in the development of supported platinum-tin catalysts, which are widely used for the normal d e h y d r o g e n a t i o n o f l o w m o l e c u l a r we i g h t parafins (propane, butane and iso-pentane). Website: http://www.lacame2014.com Email: lacame2014@lacame2014 Call for IBAME awards IBAME (the International Board of the Applications of the Mössbauer Effect) rewards two merit based prizes: 1) the IBAME Young Scientist Award for researchers up to the age of 35, for high quality contribution to science based on research that involves application of the Mössbauer Effect and 2) the IBAME Science Award for a high quality contribution to science based on research that involves application of the Mössbauer Effect over an extended period of at least 20 years. Nominations should be submitted by two persons active in research related to applications of the Mössbauer Effect, at least one of whom is a current IBAME member. And they should be sent to the IBAME secretary Michael Reissner (reissner@tuwien.ac.at) and should include: one page CV; a list of publications with those involving the Mössbauer Effect highlighted; and one page statement of importance of research and significance of the Mössbauer Effect to the research. Self nominations are not permitted. The recipients of an IBAME Science Award (Young Scientist Award; Science Award) will be announced about six to eight months before ICAME2015. Awardees will be invited to present a talk at the next ICAME in September 2015 in Hamburg, Germany. Deadline for submission is October 1st, 2014. Make your nominations today.
133 Authors index Aguilar‐García, B. 19 Aguirre, W. 97 Aguirre‐Contreras, W. R. 32, 92 Akiyama, K. 25, 27, 104 Albornoz, M.F. 76 Albuquerque, A. S. 38 Amorim Lima, M. 39 Andrade, A.L. 47 André‐Filho, José 114 Appoloni, C.R. 59 Aquino, J. C. R. 20 Aragón, F. H. 20 Ardisson, J. D. 38, 47, 52, 55, 71, 76, 147, 148 Aristizabal, C. 73 Arnache, O. 81, 94 Arredondo S, P.I. 64 Ávila Pedraza, E.A. 60, 63 Avila, M. A. 93 Baggio‐Saitovitch, E.M. 12, 23, 36, 65, 66, 78,79, 84, 93 Balzuweit, K. 39, 101 Barrero, C.A. 12, 37, 64, 73, 78, 81, 84, 109, 118, 150 Bayer, P.S. 107 Beltrán, J. J. 10, 12, 37, 78, 84 Bengoa, J.F. 14 Benítez Rodríguez, E.D. 35 Betancourth, D. 95 Bravo Cabrejos, J.A 111,112 Bustamante Domínguez, A.G. 23 Bustamante, A. 85, 147 Bustos Rodríguez, H. 30, 33, 35, 60, 61, 63 Cabral Araújo, Tiago 68 Cabral‐Prieto, A. 19, 45, 57, 70, 74 Cabrera, M. 49, 93 Caetano, P.M.A. 10, 38 Camacho, K. I. 66, 79 Cardoso, C.A. 49 Carioca Fernandes, C. 39, 101 Carvalho Jr, L.B. 49 Castillo Weeks, M. 106 Cerón Loayza, María L. 111, 112, 113 Chillal, S. 36 Coaquira, J. A. H. 10, 20, 85, 87, 100, 102, 114 Cohen, R. 20 Cordeiro Silva, Gabriela 99 Corona Pérez, I. J. 57 Dias Filho, J. H. 39, 101 Domingues, R.Z. 47 Duarte Cavalcante, Luis Carlos 52, 54, 147 Ensuncho, L. 94 Escobar, L. 57, 74 Escudey, M. 76, 147 Fabris, J. D. 10, 47, 52, 54, 55, 68, 71, 76, 107, 118, 119, 121, 147, 148 Fagundes, M. 55, 147 Fajardo, Modesto 116 Félix, L. L. 114 Fernadez‐Outon, L.E. 38 Flores, E. 43 Floresta, D. L. 55, 147 Gaete, L. 76 García, K. E. 64, 73, 109 García‐R, G. 45 García‐Sosa, I. 19, 45, 74 Garg, V. K. 34, 85, 147, 148 Gattacceca, J. 56 Giffoni, M. 23 González Arias, J.U. 63 González Díaz, R. C. 57 González Neri, M. 57 Gouvêa, D. 20 Grag, V.K. 102 Granada, D. A. 95 Greneche, J.M. 64 Gvasaliya, S.N. 36 Hernández, T. 77 Herojit Singh, L. 34 Herrera, W. T. 10, 23, 66, 79 Hidalgo, P. 20 Huízar‐Félix, A. M. 77 Iida, Y. 104 Ikeoka, R.A. 59 Jaén, J.A. 7, 43, 106 Jiménez, M. 43 Klingelhöfer, Göstar 54 Kubuki, S. 10, 25, 27, 104 Landauro, C.V. 50 Legarra, E. 77 León Félix, L. 85, 100, 102 Litterst, F.J. 36 Litterst, J. 10, 23 López, J. L. 10, 39, 101 López, L.A. 94 López‐Castañares, R. 19, 70, 74 Lozano, D. Oyola 30, 35, 60, 61, 63, 95 Lushnikov, S.G. 36 Macedo, A. L. 71 Macedo, W.A.A. 38 Machala, Libor 13 Maciel, J.C. 49 Mantilla, J. 85, 100, 102 Marchetti, S.G. 14 Márquez, M. 109
134 Martínez Ovalle, S. A. 110 Martinez, A. I. 66, 79 Martinez, M. A. R. 85, 100, 114 Mastelaro, V.R. 107 Matos, P. R. 38 Matsuda, K. 27 Mejía, M. 51 Mena, David 116 Mercader, R.C. 7, 14, 150 Merces, A.A.D. 49 Merida, D. 77 Mesquita, João P. de 68 Mestnik‐Filho, José 114 Micklitz, H. 93 Monroy Guzman, F. 57 Morais, P.C. 85 Morales, L.A 81 Morales‐Gil, P. 65 Moreno, Maricel 110 Munayco, P. 59, 62 Munevar, J. 36, 93 Muñoz, A. 43 Nagamine, L.C.C.M. 20 Nava, N. 7, 57, 65, 74 Nishida, T. 25, 27, 104 Nomura, K. 12, 118 Olea‐Cardoso 19, 70, 74 Olea‐Mejía, O. 70 Olguín, M.T. 74 Oliveira, A. C. de 34, 85,102 Oliveira, Henrique dos S. 68 Oliveira, Luiz C. A. de 68 Oliveira, W. L. 71 Olzon‐Dionysio, D. 107 Olzon‐Dionysio, M. 49, 107 Ortega, C. 94 Ortíz Arcivar, G. 57 Osorio, J.A. 12, 37, 78, 84 Oyola Lozano, Dagoberto 10, 33, 60, 61 Paiva, D.L. 47 Paniago, R. 39, 101 Pariona, N. 66 Parise, M. 85 Passamani, Edson Caetano 31 Pati, S. S. 34 Pereira, M. C. 71, 147, 148 Pérez Alcázar, G. A. 7, 10, 35, 42, 60, 61, 63, 88, 91, 97, 116 Pérez de Berti, I.O. 14 Pérez‐Alcázar, G. A. 86 Piamba Jimenez, Jeferson 116 Piamba, J. F. 42, 86, 90, 91 Pillaca, M. 50 Pires, M. J. M. 68, 71, 107 Pizarro, C. 76 Plazaola, F. 77, 147 Punnoose, A. 12, 37 Quispe‐Marcatoma, J. 50, 66, 79 Ramos, J. 42 Reguera, Edilso 18 Reyes Caballero, F. 110 Ribeiro, R. 93 Rocha Cabrera, R. 50 Rochette, P. 56 Rodríguez, H. 95 Rojas Martínez, Y. A. 30, 33, 35, 60, 61, 63 Rojas, Y. A. 35, 61, 95 Ruiz Saldarriaga, E. 97, 98 Sá Oliveira, D. M. 39 Sá Teles, José J. 68 Salazar, H. 109 Salcedo‐Castillo, U. 70 Sánchez Shepa, Héctor 116 Sánchez, H. 42, 78 Sánchez, L.C. 12, 78, 84, 94 Sanchez, P. 76 Sandoval‐Nandho, A. 19 Santos Valladares, L. De Los 85 Santos, E. Dos 56, 59, 62 Schönhöbel, A.M. 32, 92 Scorzelli, R. B. 56, 59, 62, 147, 148 Shaplygina, T. 36 Sharma, Virender K. 13 Shigeyosi, W. T. 49, 107 Sierra, G.A. 81 Sinkó, K. 25 Siskova, Karolina 13 Soares Meneses Lage, Maria Conceição 54 Sousa Bezerra da Silva, Heralda Kelis 52 Souza Dinóla, Isabel Cristina 99 Souza, S. D. de 49, 107 Souza, S. de 107 Tabares, J. A. 43, 86, 88, 97, 110 Takahashi, Y. 10, 25 Trujillo Hernandez, J. S. 88, 97 Trujillo, A. 51 Uemura, Y. J. 93 Urquijo, J.P. 83 Vargas Fontalvo, F. M. 60, 63 Velásquez, A. A. 83 Venegas, S. 83 Wright, V. 51 Xingu‐Contreras, E. 45 Zamora, L. 97 Zamora, Ligia E. 86 Zboril, Radek 13 Zeballos‐Velásquez, E. 51 Zheludev, A. 36
135

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Libro resumenes lacame 2014

  • 2.
    EDITADO POR: AgustinCabral Prieto (ININ) Eduardo Carpiette (Dirección de Educación Continua ya Distancia – UAEM) Lorena Nara (IPN) Tobías Noel Nava (IMP) Oscar Olea (Facultad de Química-UAEM) IMPRESO Metepec, Estado de México. Octubre 2014 DISEÑO: Dirección de Educación Continua ya Distancia – UAEM
  • 3.
    Índice de trabajos LACAME 2014 ..................................................................................................................................................... 1 Topics .................................................................................................................................................................. 2 Latin American Conference on the Application of Mössbauer Spectroscopy .................................................... 3 25 AÑOS DE CONGRESOS LATINOAMERICANOS DE ESPECTROSCOPÍA MÖSSBAUER................................. 5 Committees ........................................................................................................................................................ 7 Sponsors ............................................................................................................................................................. 8 Thanks ................................................................................................................................................................ 9 SCIENTIFIC PROGRAM ...................................................................................................................................... 10 Invited Speakers ............................................................................................................................................... 11 T02: CONTRIBUTIONS OF MÖSSBAUER SPECTROMETRY TO THE STUDY OF SOME OXIDE DILUTED MAGNETIC SEMICONDUCTORS: A CRITICAL REVIEW .......................................................................... 12 T05: CHEMISTRY AND ENVIRONMENTAL APPLICATIONS OF HIGH‐VALENT IRON‐OXO SPECIES ................ 13 T05: DESIGN OF SELF AND MATRIX‐SUPPORTED SYSTEMS OF IRON OXIDE NANOPARTICLES FOR CATALYTIC APPLICATIONS ................................................................................................................... 14 Participations .................................................................................................................................................... 15 T02: MÖSSBAUER SPECTROSCOPY AS SOURCE OF COMPLEMENTARY A PRIORI INFORMATION TO SOLVE CRYSTAL STRUCTURES FROM XRD POWDER DATA ............................................................................. 18 T02: NUMERICAL ANALYSIS OF BROAD MÖSSBAUER SPECTRA BY USING SIMPLE DISTRIBUTION FUNCTIONS .......................................................................................................................................... 19 T02: STRUCTURAL AND HYPERFINE PROPERTIES OF M‐DOPED SNO2 (M=TRANSITION METAL OR RARE EARTH ELEMENT) NANOPARTICLES ..................................................................................................... 20 T04: SYNTHESIS AND CHARACTERIZATION OF MAGNETITE NANOPARTICLES FUNCTIONALIZED WITH CARBOXYL AND AMINO ACIDS FOR BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS ................. 23 T05: PHOTOCATALYTIC EFFECT AND MÖSSBAUER STUDY OF IRON TITANIUM SILICATE GLASS PREPARED BY SOL‐GEL METHOD ........................................................................................................................... 25 T06: 57Fe‐MÖSSBAUER STUDY OF ZIRCONIA CONTAINING IRON VANADATE CLYSTALLIZED GLASS WITH HIGH ELECTRICAL CONDUCTIVITY ....................................................................................................... 27 T08: CORRELATION BETWEEN MILLING TIME OF POWDER, AND THE TEMPERATURE OF SUBSTRATE ON THE PROPERTIES OF NdFe THIN FILMS ................................................................................................ 30 T08: IN γ‐Fe2MnGa COMPOUND DO Fe AND Mn ORDER MAGNETICALLY AT THE SAME TEMPERATURE? DO THEY COUPLE PARALLEL OR ANTIPARALLEL AT LOW TEMPERATURES? ....................................... 31
  • 4.
    T08: MAGNETIC PROPERTIESOF TWO CORE/SHELL NANOPARTICLES COUPLED VIA DIPOLAR INTERACTION ............................................................................................................................................................. 32 T08: MÖSSBAUER AND STRUCTURAL STUDY OF ALLOYS Fe1‐XVX OBTAINED BY MECHANICAL ALLOYING .. 33 T08: MÖSSBAUER INVESTIGATIONS ON THE DESORBTION OF HYDROGEN AND HYDROXYL FROM THE IRON OXIDE NANOPARTICLES .............................................................................................................. 34 T08: MÖSSBAUER STUDY OF ALLOYS Fe67.5Ni32.5, PREPARED BY ALLOY MECHANICAL ................................ 35 T08: SPIN DYNAMICS IN COEXISTING ANTIFERROMAGNETIC AND SPINGLASS STATES OF MULTIFERROIC LEAD PEROVSKITES .............................................................................................................................. 36 T08: STUDY OF STRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF Fe DOPED, Co DOPED, AND Fe‐Co CO‐DOPED ZnO .................................................................................................................................... 37 T08: SYNTHESIS AND CHARACTERIZATION OF NixCo1‐xFe2O4 Nanoparticles ................................................ 38 T08: SYNTHESIS OF SILVER ‐COATED MAGNETITE NANOCOMPOSITE FUNCTIONALIZED BY AZADIRACTHA INDICA .................................................................................................................................................. 39 T10: MÖSSBAUER AND XRD CHARACTERIZATION OF THE PHASE TRANSFORMATIONS IN A Fe‐Mn‐Al‐C AS. CAST ALLOY DURING TRIBOLOGY TEST ................................................................................................ 42 T10: STRUCTURAL STUDY ON Li2Fe1‐xNixSiO4 ............................................................................................... 43 Posters .............................................................................................................................................................. 44 Authors index ................................................................................................................................................. 133
  • 5.
    1 LACAME 2014 XIVth Latin American Conference on the Applications of the Mössbauer Effect ‐ LACAME 2014 LACAMEs are special scientific events. They are regional meetings that aim at stimulating the development of Mössbauer Spectroscopy (MS) in Latin American countries, all of them with unparallel common cultural roots, but most of them with limited resources. MS is a particular technique suitable for promoting the scientific development in these societies. The organization of a conference like LACAME gives the young scientists of the region who do not have many chances to visit other laboratories or attend the ICAME meetings the opportunity to improve their scientific progress, and brings to the scientific communities and young researchers the feeling of how experimental physics can be performed at a high level. As a consequence of these meetings, the Mössbauer community is growing in Latin America. New laboratories have been set up and the improvement of the existing ones has been observed. The collaboration, interchange and scientific agreements between laboratories, some of them isolated prior to the LACAME conferences, have been greatly enhanced. The XIVth Latin American Conference on the Applications of the Mössbauer Effect ‐ LACAME 2014 will be held from November 10th to 14th, 2014 in Mexico. LACAME started in 1988 in Rio de Janeiro and has grown steadily since then, changing the venue every two years from different nations where Mössbauer research laboratories exist. We do believe that the special ingredient added by LACAME will help flourish the development of science and MS in this part of the world; let us hope this trend continues growing. We welcome you all to LACAME‐2014. November 2014.
  • 6.
    2 Topics T01‐Advances in experimentation and Data Processing T02‐ Amorphous, Nanocrystals and Nanoparticles T03‐ Applications in Soils, Mineralogy, Geology, Cements and Archaeology T04‐ Biological and Medical Applications T05‐ Catalysis, Corrosion and Environment T06‐ Chemical Applications, Structure and Bonding T07‐ Industrial Applications T08‐ Magnetism and Magnetic Materials T09‐ Multilayers, Thin Films and Artificially Structured Materials T10‐ Physical Metallurgy and Materials Science
  • 7.
    Latin American Conferenceon the Application of Mössbauer Spectroscopy 3 Elisa Baggio Saitovitch We can not speak about Mössbauer spectroscopy in Latin America without speaking about Jacques Danon who passed away in 1989. He has initiate to work already in 1960 in this field at Brazilian Center for Research in Physics (CBPF), in Rio de Janeiro. He always insisted that we should not compete with the countries of north hemisphere but exercise our creativity in scientific research, looking for topics related with our region or having a new approach in frontier topics, addressing topics that can be studied in the frame of the scientific and technologic difficulties (not facilities). He always said: Lo que es importante, no son las técnicas y computadores, son las ideas. Solamente la creatividad puede generar un verdadero progreso tanto en la ciencia como en cualquier campo de la actividad humana. In the early days of Mössbauer spectroscopy in Latin America there was more interaction; this was not the case when I started to work in Mössbauer spectroscopy. Danon always mentioned collaboration with Augusto Moreno y Moreno, in Mexico, Carlos Abeledo and Albert Fech. He published the first lectures in Spanish on the Mössbauer effect given at the Escuela Latino Americana de Física that was held in Mexico, in 1968. In 1985, while participating in a commission to discuss the future of CLAF (Latin American Center for Physics) I realized how bad the scientific collaboration among Latin American groups doing research was; they tend to give priority to the interaction with groups in north hemisphere. The collaboration with our neighbors in Latin America would not occur spontaneously, it was necessary to be worked out because, more than the proximity, they have common problems. With these ideas in mind I went to a Brazilian meeting in Mössbauer spectroscopy, which was the last from a series going through all the groups (see H. Rechenberg report). Our idea was to change a bit the scope including all Brazilian groups working in Hyperfine Interaction. There I have made another proposition: open the meeting to all the Mössbauer groups in Latin America. This proposition was accepted and I suggested that the Chairperson should be Jacques Danon, knowing that I should do the heavy work. In November 1988 we organized in Rio, with the help of Rosa Scorzelli the first LACAME; the name of our meeting was inspired in the ICAME. At those days we were able to bring together more than 129 participants! I believe that most of the people working in this area came to Rio. It was difficult to contact all the people, in this case the contribution of Danon
  • 8.
    was essential: heknew everybody. But there was no e‐mail, no telephone and the best communication was by telegram and fax. For the first time I learned about Raiza from Havana, Jaen in Panama or Aburto in Mexico. The situation in Brazil in 1989 was very favorable for our purpose; the inistry of Science and Technology had been just created. I was able to get support from several Brazilian institutions and foundations as CBPF, CNPq, CNEN, FINEP, CAPES and CLAF. The total budget was about US$ 50 000 and the invitation included air ticket, hotel and meals. Circa of 10 non Latin American scientist specialists in different fields were invited and contributed to the success of the conference. I still remember how the eyes of some students were shining when they could listen to these known specialists in Mössbauer spectroscopy. All the effort was worthwhile! After that we had the nice meeting in Cuba with the conversation with Fidel Castro and many non Latin American participants. Argentina, Chile, Peru, Colombia, Venezuela, Panama and Mexico (in 2004), it has been a long way, with a lot of efforts (the chair persons know it well), but the result is excellent. The number of participants has decreased along these 15 years. May be there is now less people in the field or less funds available, this we still need to find out. In Brazil the strong group of Porto Alegre, where I was introduced to Mössbauer spectroscopy, has only a minor activity and sometimes does not participate even in the Brazilian meetings. To compensate now we have the group of Vitoria and Ouro Preto, which are very active and have organized the last Brazilian meetings. New groups have been created in Peru (Victor Peña Rodrigues) and Colombia (Perez Alcazar) and they are very active as we could see in the last conferences. From the successive meetings we can follow the development of some students like Restrepo from Colombia. He gave a talk in Caracas as a senior scientist! Despite this conference became smaller they are very dynamic with a lot of discussion and interesting questions. I hope we can keep this atmosphere for Mexico. This meeting have been very important for the participants, researchers and students that do not have the opportunity to participate in the ICAMEs. Traditionally some few non Latin American specialists are invited speakers together with local researchers from areas where Mössbauer spectroscopy can be applied. For example, in Venezuela we had some talk about Petroleum industry. We try to avoid inviting the same non Latina American specialists in two successive meetings in order to cover different areas. The LACAME has contributed for the collaboration among LA groups and for spreading this spectroscopy in LA. All the applications are being studied, including minerals, meteorites, soils, superconducting and magnetic materials, milling, catalyses, corrosion, chemistry, thin films, heavy fermions, 4
  • 9.
    etc. However westill hope to be able to improve the shearing of the facilities among the groups and establish bilateral official exchange programs. On a regular basis the LACAME conferences are organized in Latin America, each two years and we succeeded in organizing and reinforcing the collaboration among the Mössbauer community in Latin America. Except for the conference in Chile the Proceedings have been published by Hyperfine Interaction. 25 AÑOS DE CONGRESOS LATINOAMERICANOS DE ESPECTROSCOPÍA MÖSSBAUER Por estos días se están cumpliendo los 25 años de nuestra existencia como comunidad latinoamericana de espectroscopía Mössbauer. Es con enorme alegría que queremos celebrar este aniversario. En 1988, con la excepción de Brasil, que realizaba desde1982 encuentros locales de jóvenes investigadores, en nuestro continente había algunos laboratorios dispersos con investigadores que pretendíamos hacer buena ciencia sin muchos medios a pesar las grandes dificultades que se presentaban en nuestros países. Esto cambiaría para siempre cuando, entre el 31 de octubre y el 4 de noviembre de 1988 se organizó el primer Congreso Latinoamericano de Espectroscopía Mössbauer. Allí nos conocimos y rápidamente nos identificamos como formando parte de una comunidad científica. En estos veinticinco años, hemos crecido individual y colectivamente y nos sentimos miembros de una realidad que trasciende las fronteras de nuestros países para constituirse en una unidad latinoamericana que encuentra gran placer y ventaja en colaborar con colegas de otros países de la región y reencontrarse con viejos (y no tan viejos) amigos cada dos años en los LACAME y en numerosas colaboraciones entre distintos miembros de la comunidad. En este tiempo hemos visto aparecer laboratorios de luz sincrotrón, centros de microscopía electrónica, la Internet. En nuestras propias instituciones se han agregado nuevas técnicas que como la calorimetría o la magnetometría nos han permitido profundizar enormemente nuestras investigaciones. Sin embargo, todo esto no ha desviado nuestra convicción de que lo que nos une es la espectroscopía Mössbauer. En otros continentes esta realidad es de mucha menor intensidad o simplemente no existe ya. Pero ciertamente en América latina nuestros congresos gozan de prestigio y de entusiasmo, con nuevos jóvenes que se sienten parte de esta comunidad convocante que tiene un gran reconocimiento internacional. 5
  • 10.
    Por eso, elComité Latinoamericano de Espectroscopía Mössbauer saluda jubilosamente a los colegas latinoamericanos y hace votos para que las nuevas generaciones tengan éxito en sus esfuerzos de continuar y mejorar lo que ya ha sido hecho hasta aquí. 6
  • 11.
    7 Committees IntenationalCommittee E.M. Baggio Saitovitch CBPF Brazil N.R. Furet Bridón CNIC Cuba F. González Jiménez UCV Venezuela J.A. Jaén UP Panamá R.C. Mercader UNLP Argentina N. Nava IMP México V.A. Peña Rodríguez UNMSM Perú G.A. Pérez Alcázar UV Colombia Carmen Pizarro USACH Chile Local organizing committee Humberto Arriola S. Facultad de Química, Universidad Nacional Autónoma de México Agustín Cabral Prieto Instituto Nacional de Investigaciones Nucleares Naria Adriana Flores Fuentes Escuela Superior Físico‐Matemáticas, Instituto Politécnico Nacional Arturo García Borquez Escuela Superior Físico‐Matemáticas, Instituto Politécnico Nacional Eduardo Gómez Garduño DECyD, Universidad Autónoma Estado México Ezequiel Jaimes Figueroa DECyD, Universidad Autónoma Estado México Rafael López Castañares Facultad de Química, Universidad Autónoma Estado México Fabiola Monroy Guzmán Instituto Nacional de Investigaciones Nucleares Noel Nava E. Instituto Mexicano del Petróleo Oscar Olea Cardoso Facultad de Química, Universidad Autónoma Estado México Oscar F. Olea Mejia Facultad de Química, Universidad Autónoma Estado México Jesús Soberón M. Investigador
  • 12.
    8 Sponsors AbdusSalam International Centre for Theoretical Physics Sociedad Química de México Universidad Autónoma del Estado de México Consejo Mexiquense de Ciencia y Tecnología Instituto Nacional de Investigaciones Nucleares Instituto Mexicano del Petróleo
  • 13.
    9 Thanks LosComités Internacional y Local de la XIV Latin American Conference on the Applications of the Mössbauer Effect aprecian y agradecen profundamente al Rector de la Universidad Autónoma del Estado de México, Dr. en D. Jorge Olvera García, por habernos permitido realizar esta conferencia en las instalaciones de la Dirección de Educación Continua y a Distancia (DECyD‐UAEM). Así mismo, agradecemos al Maestro Ezequiel Jaimes Figueroa, Director de la DECyD‐UAEM, por todo el apoyo y facilidades que nos brindó durante la organización de dicha conferencia, así como a su equipo de trabajo por su invaluable aportación para preparar el compendio de los resúmenes que se presentan en este libro.
  • 14.
    10 SCIENTIFIC PROGRAM SUNDAY NOV. 9 MONDAY NOV. 10 TUESDAY NOV. 11 WEDNESDAY NOV. 12 THURSDAY NOV. 13 FRIDAY NOV. 14 9:00 Opening Ceremony 9:00 J A Jaen 9:00 Mira Ristic VideoC 9:00 Elisa Baggio‐ Saitovitch 9:00 Roberto C. Mercader 9:30 Cesar A Barrero M 9:45 Coffee 9:45 Coffee 9:45 Coffee 10:15 Coffee 10:05 V Sharma 10:00 Coffee 10:05 F.J. Litterst 10:05 Edilso Reguera 10:35 Edson P 10:50 W. T. Herrera City tour 10:50 P.M.A. Caetano 11:10 Dagoberto Oyola Lozano 11:30 Herojit Singh 11:50 J.J. Beltrán 12:10 J. L. López 10:50 Concluding Remarks 11:20 G.A. Pérez Alcázar 11:30 S. Kubuki 11:40 José Domingos Fabris 11:50 Aguirre‐Contreras Next LACAME 12:00 Y. Takahashi, 12:10 Benítez Rodríguez 12:20 Lunch 12:30 Lunch 12:30 Lunch 14:00 Rojas Martínez 14:00 POSTER SESSION1 14:00 POSTER SESSION2 14:20 J. A. H. Coaquira 18:00 Registration Latin American Round Table 19:00 – 21:00 Welcome
  • 15.
  • 16.
    T02: CONTRIBUTIONS OFMÖSSBAUER SPECTROMETRY TO THE STUDY OF SOME OXIDE DILUTED MAGNETIC SEMICONDUCTORS: A CRITICAL REVIEW J.J. Beltrán1, A. Punnoose2, K. Nomura3, E.M. Baggio-Saitovitch4, and C.A. Barrero1 1Grupo de Estado Sólido, Facultad de Ciencias, Universidad de Antioquia, Medellín, Colombia. 2Department of Physics, Boise State University, Boise, USA 3Department of Applied Chemistry, School of Engineering, The Tokyo University, Tokyo, Japan 4Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brazil. 12 *Corresponding author: e-mail: cesar.barrero@udea.edu.co Keywords: Fe doped ZnO, Fe doped SnO2, nanoparticles. Topic: T02- Amorphous, Nanocrystals and Nanoparticles In 2005, the prestigious journal Science [1] posed a list of 125 unsolved scientific questions, one of them being: “is it possible to create magnetic semiconductors that work at room temperature?”. In 2008, Coey et al. [2] mentioned that the origin of the magnetism in Diluted Magnetic Semiconductors (DMS) is one of the most puzzling investigations. And to date we can say that the understanding of such phenomena is still a great challenge in materials science. In fact, there is no agreement between the various theoretical and experimental studies performed on the origin of the ferromagnetic signal in DMS, particularly in Oxide-DMS (ODMS). From the experimental side, the use of different characterization techniques, including Mössbauer spectrometry (MS), is an important requirement to achieve a better understanding of the phenomena. In this presentation we will show some examples of the contributions that 119Sn and 57Fe MS have done to the characterization of Fe-doped ZnO [3], Fe-Co codoped ZnO [4], Fe-doped SnO2 [5-7] and Fe-Sb codoped SnO2 [8,9] nanoparticles. We will show how this technique has contributed to the: (i) demonstration of the absence of both spurious phases and clustering of dopants, (ii) determination of the preferable sites, high or low spin character, and oxidation states of the transition metal (TM) ions, (iii) identification of the preferable location of the TM ions, either at the surface, at the interior or in the whole nanoparticles, (iv) identification and characterization of defects, (v) proper characterization of the electronic, crystallographic, and magnetic properties, and their possible relations, (vi) and determination of the TM ions that are involved in the magnetic ordering. References [1] Kennedy and Norman, Science 309 (2005) 82. [2] J.M.D. Coey, K. Wongsaprom, J. Alaria, and M. Venkatesan, J. Phys. D.: Appl. Phys. 41 (2008) 134012. [3] J.J. Beltrán, J.A. Osorio, C.A. Barrero, C.B. Hanna and A. Punnoose, J. Appl. Phys. 113 (2013) 17C308. [4] J.J. Beltrán, C.A. Barrero, A. Punnoose, J. Phys. Chem. C, V. 19 (3) (2014) [5] A. Punnoose, K. Dodge, J.J. Beltrán, K.M. Reddy, N. Franco, J. Chess, J. Eixenberger, and C.A. Barrero, J. Appl. Phys. 115 (2014) 17B534 [6] J.J. Beltrán, L.C. Sánchez, J. Osorio, L. Tirado, E.M. Baggio-Saitovitch, and C.A. Barrero, J. Mater. Sci. 45 (2010) 5002 [7] K. Nomura, C.A. Barrero, J. Sakuma, and M. Takeda, Phys. Rev. B 75 (2007) 184411 [8] K. Nomura, C.A. Barrero, K. Kuwano, Y. Yamada, T. Saito, E. Kuzmann, Hyperfine Interact. 191 (2009) 25. [9] K. Nomura, E. Kuzmann, C.A. Barrero, S. Stichleutner, and Z. Homonnay, Hyperfine Interact. 184 (2008) 57.
  • 17.
    T05: CHEMISTRY ANDENVIRONMENTAL APPLICATIONS OF HIGH-VALENT IRON-OXO SPECIES Virender K. Sharma1*, Radek Zboril2, Libor Machala2, and Karolina Siskova2 1Departent of Environmental and Occupational Health, School of Public Helath, Texas A&M University 1266 TAMU, SPH 101, College Station, Texas. 2 Regional Centre of Advanced Technologies and Materials, Departments of Experimental Physics and Physical Chemistry, Faculty of Science, Palacky University, 78371 Olomouc, Czech Republic 13 *Corresponding author: e-mail: vsharma@sph.tamhsc.edu Keywords: Ferrate, oxidation, decontamination Topic: T05- Catalysis, Corrosion and Environment The chemistry of iron has been developed early in the history of mankind as it is the basic metal of the industrial society and its ore is profoundly present globally. Iron as the most abundant transition element, present in alloy with nickel, and constitutes about a third of entire mass of the Earth’ crust. Iron is important for most of the living organisms. Iron has a unique range of valence states from zero to +6 oxidation states, which have numerous applications in medicine, energy, nanotechnology, biocatalysis, energy, and environmental remediation. Examples of biocatalysis include involvement of high-valent oxoiron(IV) (FeIV = O) and oxoiron(V) (FeV = O) species in a number of enzymatic systems (1). These high-valent iron species participate in halogenation, epoxidation, and hydroxylation reactions. In the last decade, our research group is researching the simple oxo-compounds of higher-valent iron species, commonly called ferrates (FeVIO42-, Fe(VI), FeVO43-, Fe(V), and FeIVO44-, Fe(IV)) in aqueous solution, which have shown their applications in energy materials, green organic synthesis, and waste remediation (2). Examples of remediation are oxidative transformations of toxic inorganic and organic contamination to non-toxic by products, inactivation of virus and bacteria, and removal of toxic metals (e.g. arsenic) (3, 4). The focus of the presentation will be on demonstrating the chemistry and applications of these high-valent iron species in water treatment technology. Mössbauer spectra of Fe(VI), Fe(V), Fe(IV) and Fe(III) species can be used to distinguish these iron species in the solid phase and in the solution mixture. The isomer shift values of ferrates decreased almost linearly and can be expressed as Δ (mm s-1) = 1.084 – 0.326 × OS (1) Mechanisms of the reactions of ferrates with different contaminants were studied using Mössbauer spectroscopy in conjunction with other spectroscopic and surface techniques. Figure 1 shows the example of studying the removal of arsenic by Fe(VI) in which ex-situ and in-situ removal by Fe(III), generated from Fe(VI), differ. Figure 1. Different mechanisms of arsenic removal by Fe(III), ex-situ sorption (left) and Fe(VI) induced in-situ structural incorporation (right) (5). References [1] J. Hohenberger, K. Ray, and K. Meyer, Nature Commun. 3720 (2012). [2] V. K. Sharma, Coord. Chem. Rev. 257 (2013) 494-510. [3] E. Casbeer, V.K. Sharma, Z. Zajickova, and D.D. Dionysiou, Environ. Sci. Technol., 47 (2013), 4572-4580. [4] V.K. Sharma, J. Environ. Manage. 92 (2011), 1051-1073. [5] R. Prucek, J. Tucek, J. Kolařík, J. Filip, Z. Marušák, V.K. Sharma, and R. Zboril, Environ. Sci. Technol. 47 (2013) 3283-3292.
  • 18.
    T05: DESIGN OFSELF AND MATRIX-SUPPORTED SYSTEMS OF IRON OXIDE NANOPARTICLES FOR CATALYTIC APPLICATIONS I.O. Pérez de Berti1, J.F. Bengoa1, S.G. Marchetti1, R.C. Mercader2* 1CINDECA, CONICET, CICPBA, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 47 Nº 257, 1900 La Plata, Argentina 2 Instituto de Física La Plata, CCT-CONICET, Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 115 y 49, 1900 La Plata, Argentina *Corresponding author: e-mail: mercader@fisica.unlp.edu.ar Keywords: Fischer-Tropsch reaction, semi-model catalysts, Mössbauer characterization, pre-synthesized nanoparticles Topic: T05- Catalysis, Corrosion and Environment 14 Metallic nanoparticles are widely used as supported catalysts in many industrial chemical reactions. A detailed understanding of the enhancement that the nanoparticles bring about in the stability, activity, and selectivity of the solids requires quasi-model catalysts with well-defined surfaces and supported nanoparticles of homogeneous size. The usual way of synthesizing catalysts of supported nanoparticles is to impregnate the solid with a solution that contains the metal salts that will give rise to the catalyst. However, this route doesn't necessarily lead to a catalyst close to the ideal conditions. The Fischer-Tropsch synthesis is a reaction in which a mixture of hydrogen and carbon monoxide converts into liquid hydrocarbons mediated by the presence of a catalyst. The reaction process can be written as: nCO + (2n+1) H2  CnH2n+2 + nH2O In spite that it was developed in the 1920s and that it has been intensively used over many decades, the intrinsic mechanism of how it proceeds is not fully known. In particular, the activity and selectivity depend on factors that are not easy to isolate. One of them is the so-called structure sensitivity. To be able to study the diverse influence of the different parameters in the activity and selectivity of the catalysts, we set about to prepare quasi-model catalysts by a route different from the usual one; we pre-synthesized systems of narrowly size-distributed nanoparticles and introduced them afterwards into the already synthesized matrix. In this talk we will describe the results obtained after the preparation of Fischer-Tropsch catalysts made up 3 nm maghemite nanoparticles supported on SBA-15 matrices. The catalysts were prepared by pre-synthesizing γ-Fe2O3 particles and further embedding them into a modified SBA-15 matrix. The results showed that the solid kept its structural properties over impregnation, activation and catalytic reaction performed in realistic conditions. Out of the many techniques by which we characterized the solids, Mössbauer spectroscopy was the one that yielded the more helpful results allowing the identification of all the relevant intervening iron species. Figure 1. Mössbauer spectra of γ-Fe2O3/SBA-15 catalysts measured at the temperatures indicated after a catalyst reaction conducted at 20 atm. As an example of the results that will be considered in the talk, Fig. 1 displays the Mössbauer spectra of two catalysts that produced a high activity and a good olefin/paraffin ratio over the Fischer-Tropsch reaction at 20 atm after being activated in a CO-H2: CO atmosphere (left) and H2 atmosphere (right). Both solids underwent catalysis tests and were measured in a specially designed cell that enabled keeping the same reactor atmosphere when taken over to the Mössbauer spectrometer.
  • 19.
  • 20.
    T01‐ Advances inexperimentation and Data Processing 16
  • 21.
    T02‐ Amorphous, Nanocrystalsand Nanoparticles 17
  • 22.
    T02: MÖSSBAUER SPECTROSCOPYAS SOURCE OF COMPLEMENTARY A PRIORI INFORMATION TO SOLVE CRYSTAL STRUCTURES FROM XRD POWDER DATA Edilso Reguera Center for Applied Science and Advanced Technology, Legaria Unit, National Polytechnic Institute, Mexico, D. F., Mexico; Corresponding author: e-mail: edilso.reguera@gmail.com Topic: T02- Amorphous, Nanocrystals and Nanoparticles Mössbauer spectra provide information on the coordination geometry for the atom involved in the - resonant nuclear absorption, on the nature of first and second neighbors, and on its electronic structure and relative occupation of structural sites in the solid. All this information is relevant to solve the crystal structure of new materials from XRD powder data. To solve the crystal structure of a new material the best option is to have diffraction data from a single crystal. Such possibility is available only for a small fraction, usually < 10 %, of practical situations. In a single crystal experiment, the diffraction pattern is the Fourier Transform for the sample in the inverse space and the crystal model to be refined (in the direct space) is obtained from the Inverse Fourier Transform of the recorded diffraction pattern. In XRD powder experiment, the 3D structural information is projected in 1D space. From this fact, the crystal structure for this kind of data must be solved through an ill-posed problem. This supposes the availability of a priori structural information or boundary conditions for the mathematical problem to be solved. Such a priori information is usually obtained from spectroscopic techniques. Nuclear, electronic and vibrational spectra contain information on the local symmetry (coordination geometry) and nature of the first neighbors for the atom(s) involved resonant absorption and re-emission. In this contribution, the scope of Mössbauer spectroscopy in that sense is discussed, from several illustrative examples, where the crystal structure was solved and then refined, using the corresponding Mössbauer spectra as source of the required a priori structural information. 18
  • 23.
    T02: NUMERICAL ANALYSISOF BROAD MÖSSBAUER SPECTRA BY USING SIMPLE DISTRIBUTION FUNCTIONS B. Aguilar-García1, A. Sandoval-Nandho1, I. García-Sosa2 O. R. López-Castañares3, O. Olea-Cardoso3 and A. Cabral-Prieto2(*) 1Universidad Autónoma Metropolitana-Cuajimalpa, Avenida Vasco de Quiroga 4871, Cuajimalpa, Santa Fe Cuajimalpa, 05300 Ciudad De México, D.F. 2 Instituto Nacional de Investigaciones Nucleares, Departamento de Química, Apdo. Postal 18-1027, Col. Escandón, Deleg. M. Hidalgo, C. P. 11801, México. D. F., México. 3Universidad Autónoma del Estado de México, Paseo Universidad #100, Universitaria, 50130 Toluca de Lerdo, Estado de México *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: Broad Mössbauer spectra, hyperfine distributions, goettite Topic: T02- Amorphous, nanocrystal and nanoparticles 19 The analysis of broad Mössbauer spectra is usually handled by using the convolution between the Gaussian and Lorentzian lines. There are, however, many cases were this convolution does not give meaningful results because the Mössbauer spectra are the result of a complex superposition of several patterns and the discrete hyperfine parameters are difficult to calculate from them. In such cases the use of hyperfine distribution functions are preferred [1]. In this paper simple distribution functions are used to analyze the Mössbauer spectrum of Goethite nanoparticles. The asymmetrical triangle is shown in Fig. 1. Figure 1 (a) Mössbauer spectrum of goethite nanoparticles recorded at 77K. (b) Asymmetrical triangular distribution function may be used to properly fit this spectrum. Typical representations of the hyperfine field distributions (HFD) for this nano material are as shown in Fig. 2 (a) and (b), obtained with known methods [1, 2]. Figure 2. (a) Step distribution function [1], (b) Fourier series expansion [2]. Figure 3. (a) Gaussian, (b, c) Rational, (d) binomial distribution functions. Figure 3 shows, on the other hand, three atypical representations of the HFD. The decaying curve, after the maxima, does not appear which seems to be unnecessary for cases like this. If it does such a decay is abrupt as indicated in figs. 1 (a). Fig. 2 (a) and (b) or Fig. 3 (b). In all these cases there is always a question left: what of the seven HFDs, here presented, represents best the experimental data. Morup et al. [3] reproduces the asymmetry of a Mössbauer spectrum by using an asymmetrical distribution function for the crystal size of nanomaterials. Thus, Fig. 3 (d) may be the best searched solution instead of Fig. 2 (b). In all presented cases the same order of magnitude for squared Ji is, however, acceptable. References [1] J. Hesse, A. Rübartsch, Journal of Physics E 7 (1974) 526. [2] Window, B.: J. Phys. E: Sci. Intrum. 4, 401 (1971) [3] S. MØrup , H. TopsØe and J. Lipka, Journal de Physique Colloque C6, sup.12, Tome 37, (1976) C6- 287.
  • 24.
    T02: STRUCTURAL ANDHYPERFINE PROPERTIES OF M-DOPED SNO2 (M=TRANSITION METAL OR RARE EARTH ELEMENT) NANOPARTICLES J. A. H. Coaquira1, F. H. Aragón1, J. C. R. Aquino1, R.Cohen2, L.C.C.M. Nagamine2, P. Hidalgo3, D. Gouvêa4 1Instituto de Física, Universidade de Brasília, Núcleo de Física Aplicada, Brasília DF 70910-900, Brazil. 2 Instituto de Física, Universidade de São Paulo, SP 05508-090,Brazil 3Faculdade Gama-FGA, Sector Central Gama, Universidade de Brasília, Brasília, DF 72405-610, Brazil. 4Departamento de Metalurgia e Engenharia de Materiais, Escola Politécnica, Universidade de São Paulo, São Paulo SP 05508-900, Brazil. *Corresponding author: e-mail: coaquira.ja@gmail.com Keywords: M-doped SnO2 nanoparticles, Mössbauer spectroscopy, structural properties Topic: T02- Amorphous, Nanocrystals and Nanoparticles The possibility of using the magnetic properties of magnetic gas sensing materials instead of their conventional electrical properties is moving forward the interest for dilute magnetic semiconductor oxides. The SnO2 compound is a wide band-gap (~3.5 eV) semiconductor and widely used as a conventional gas sensor due to its high reactivity with environmental gases. The doping of this semiconductor using transition metals changes its sensitivity, selectivity and time response with respect to a number of pollutant gases. However, the use of magnetic gas sensors requires that the sensing material shows magnetic order above room temperature. Although reports indicate room temperature ferromagnetic properties of transition-metal- doped SnO2 thin films and powders, the origin of that order is not clear yet [1]. 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 10.0 mol% 5% 2.5 mol% Transmission (a. u.) 7.5 mol% P (QS) P (QS) QS (mm/s) P (QS) QS (mm/s) P (QS) QS (mm/s) 0.0 mol% -8 -6 -4 -2 0 2 4 6 8 Velocity (mm/s) 0 1 2 3 4 5 6 7 QS (mm/s) 12 Experimental data 8 4 0 -4 Figure 1. Room-temperature Mossbauer spectra of Gd-doped SnO2 nanoparticles. Isomer shift (IS) as a function of the Gd content. In this work, we report the study of the structural and magnetic properties of M-doped SnO2 (M=transition metal or rare earth element) nanoparticles synthesized by a polymer precursor method [2]. X-ray diffraction patterns indicate the formation of only the rutile phase for the whole set of samples. Undoped SnO2 nanoparticles show an average particles size of ~11 nm and this size shows a decreasing tendency as the M content is increased, regardless the M dopant. This crystalline size is further corroborated by TEM images. Magnetic measurements, carried out in a wide range of temperature and applied magnetic field, suggest the coexistence of ferromagnetic and paramagnetic phases. Depending on the dopant content, a ferromagnetic behavior which survives until high temperatures is determined. Mössbauer spectra, carried out using a Ca119mSnO3 radiation source, show no evidences of magnetic splitting and, depending on the doping element (M), room temperature Mössbauer spectra are well resolved by considering doublets. The origin of these doublets and the effects on the quadrupole splitting and isomer shift due to the doping are discussed in this work. References [1] W. Wang, Z. Wang, Y. Hong, J. Tang, and M. Yu, J. Appl. Phys. 99 (2006) 0M115. [2] D. Gouvêa, A. Smith, J. P. Bonnet, Eur. J. Solid State Inorg. Chem. 33 (1996) 1015. 0 2 4 6 8 10 -8 IS (x10-3mm/s) Gd content (%)
  • 25.
    T03‐ Applications inSoils, Mineralogy, Geology, Cements and Archaeology 21
  • 26.
    T04‐ Biological andMedical Applications 22
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    T04: SYNTHESIS ANDCHARACTERIZATION OF MAGNETITE NANOPARTICLES FUNCTIONALIZED WITH CARBOXYL AND AMINO ACIDS FOR BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS W. T. Herrera1, A.G. Bustamante Domínguez1, M. Giffoni2, E. Baggio-Saitovitch2 and J. Litterst3 1 Ceramics and Nanomaterials Laboratory, Department of Physics, National University of San Marcos (UNMSM), A.P. 14-0149, Lima 14, Perú. 2 Brazilian Center for Physics Research (CBPF), 22290-180, Rio de Janeiro, Brazil. 3 Institute for Physics of Condensed Matter, Technische Universität Braunschweig (TU Braunschweig), Mendelssohnstrasse 3, D-38106 Braunschweig, Germany. *Corresponding author: e-mail: wiliam@agdes.pe Keywords: magnetite nanoparticles functionalized, magnetic nanoparticles Topic: T04 - Biological and Medical Applications 23 This work involves the synthesis of magnetite nanoparticles (NPs) functionalized with lauric acid (LA), oleic acid (OA) and lysine (Lys). The synthesis was carried out using a chemical route of co-precipitation. This route allows the production of NPs functionalized using a basic infrastructure, low cost of production, the latter very important, especially if we consider the potential applications in the field of environmental remediation. In the case of biomedical applications also chemical route is the best alternative in this case however requires a more extensive characterization and clinical trials. After synthesis of functionalized NPs these were characterized with the techniques: X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy (MS), vibrating sample magnetometry (VSM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). Of the analysis made by the different techniques we concluded that functionalized NPs are of very good quality. All were magnetic with magnetic saturation of 60 emu/g, for the case of NPs coated with AL. The XRD and TEM measurements show that the NPs have an average size between 9 and 11 nm with spinel crystal structure with lattice parameter of 8.37 Å. XPS measures determined that iron atoms has a valence of +3 and +2, with a total ratio of iron atoms Fe3+:Fe2+ of 2:1. Of the FTIR measurements we show that AL and AO molecules are chemically bound to the surface of the NPs. By TGA measures we calculate the number of functionalized molecules. In the case of NPs coated with AL and AO were 1974 and 1486, respectively. References [1] Gupta, A.K., Gupta, M., Biomat. (2005) 26, 3995. [2] Kas, R., Sevinc, E., Topal, U., Acar, H.Y., J. Phys. Chem. (2010) 114, 7758. [3] Tsedev Ninjbadgar, et al, Solid State Sciences 6, (2004) 879–885. [4] Katerina Kluchova et al. Biomaterials 30 (2009) 2855–2863.
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    T05‐ Catalysis, Corrosionand Environment 24
  • 29.
    T05: PHOTOCATALYTIC EFFECTAND MÖSSBAUER STUDY OF IRON TITANIUM SILICATE GLASS PREPARED BY SOL-GEL METHOD Y. Takahashi1*, S. Kubuki1, K. Akiyama1, K. Sinkó 2 and T. Nishida3 1Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi-Oji, Tokyo 192-0397, JAPAN 2Institute of Chemistry, Faculty of Science, Eötvös Loránd University, Pázmány P.s. 1/A, Budapest 1117, 25 Figure 1. XRD patterns of FSxTi with 'x' of (A) 10 and (B) 40 annealed at (a) 400 oC and (b) 1000 oC for 3h. 102 100 98 96 94 92 90 100 95 90 85 (A-a) (A-b) (B-a) (B-b) Figure 2. FeMS of FSxTi with 'x' of (A) 10 and (B) 40 annealed at (a) 400 oC and (b) 1000 oC for 3h. HUNGARY 3Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN *Corresponding author, e-mail: takahashi-yusuke3@ed.tmu.ac.jp Keywords: photocatalyst, silicate glass Topic: T05- Catalysis, Corrosion and Environment 1. Introduction Anatase type TiO2 is well known as a photocatalyst activated by the UV light [1]. It will be more effective to develop photocatalysts which show their activity under visible light irradiation. Recently, Takahashi et al. reported that 50Fe2O3·50SiO2 (in mass %) glass had photocatalytic activity under the visible light [2]. This result implies that iron silicate glass might be a practical photocatalyst with high efficiency. In this study, we report a relationship between local structure and visible light activated photocatalytic effect of iron titanium silicate glass prepared by sol-gel method. 2. Experimental Iron titanium silicate glasses with a composition of 50Fe2O3•(50-x)SiO2·xTiO2 (in mass %, x = 10-40, abbreviated as FSxTi) were prepared by sol-gel method. Reagent chemicals of Si(OC2H5)4, Fe(NO3)3•9H2O, Ti(OCH(CH3)2)4, HNO3, and C2H5OH were poured into a beaker and well mixed for 2 h at RT. After having been agitated by reflux-heat method at 80 oC for 2 h, the solution was poured into a glass vial and dried at 60 oC for 3 days to obtain dark brown gel samples. The samples were annealed between 400 and 1000 oC for 3 h in air. For the structural characterization, 57Fe-Mössbauer spectra (FeMS) were measured by a constant acceleration mode with a source of 57Co(Rh) with -Fe as a reference and X-ray diffractmetry (XRD) was carried out at 2θ between 10° and 80° with an interval and scanning rate of 0.02° and 5° min-1, respectively. X-ray with the wavelength of 1.54 Å generated by Cu filament was targeted by electron accelerated by 300 mA and 50 kV. 3. Results and Discussion As shown in Figs. 1 (A-a) and (B-a), XRD patterns of FSxTi with x of 10 and 40 annealed at 400 oC showed halo patterns due to amorphous structure, while intensive diffraction peaks attributed to crystalline phases of Fe2TiO5, -Fe2O3 and TiO2 were observed when annealed at 1000 oC (Figs. 1 (A-b) and (B-b)). FeMS of FS10Ti annealed at 1000 oC for 3 h showed a sextet with  of 0.38 mm s-1,  of - 0.22 mm s-1and int of 50.6 T due to α-Fe2O3 and a doublet with  of 0.38 mm s-1 and  of -10 -5 0 5 10 Velocity / mms-1 -10 -5 0 5 10 Velocity / mms-1 105 100 95 90 85 80 100 98 96 94 92 90 0.76 mm s-1 due to Fe2TiO5 (Fig. 2 (A-b)). - Fe2O3 could not be detected from the XRD pattern and the FeMS of FS40Ti annealed at 1000 oC. These results indicate that the kinds and fraction of crystalline phases precipitated in FSxTi can be controlled by the annealing conditions and the chemical composition. The photocatalytic effect of FSxTi is presented on the day of the conference. References [1] A. Fujishima, K. Honda, Nature 238 (1972) 37-38. [2] Y. Takahashi, S. Kubuki, K. Akiyama, K. Sinkó, E. Kuzmann, Z. Homonnay, M. Ristić, T. Nishida, Hyperfine. Interact. 226 (2014) 747-753
  • 30.
    T06‐ Chemical Applications,Structure and Bonding 26
  • 31.
    T06: 57Fe-MÖSSBAUER STUDYOF ZIRCONIA CONTAINING IRON VANADATE CLYSTALLIZED GLASS WITH HIGH ELECTRICAL CONDUCTIVITY K. Matsuda1, S. Kubuki1*, K. Akiyama1 and T. Nishida2 1 Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi-Oji, Tokyo 192-0397, JAPAN. 2 Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN. *Corresponding author: e-mail: kubuki@tmu.ac.jp Keywords: vanadate glass, electron hopping, heat-treatment, monoclinic vanadium-zirconia, beta-vanadium bronzes Topic: T06- Chemical Applications, Structure and Bonding 100 98 96 100 98 96 27 Introduction Vanadate glass is known as a semiconductor with the electrical conductivity () of 10-7-10-5 S cm-1 due to 3d electron (polaron) hopping from VVI (or VIII) to VV [1]. A drastic increase in  of up to 100 Scm-1 was observed for barium iron vanadate glass, BaO-Fe2O3- V2O5 caused by heat treatment (HT), which has a registered trademark of ‘NTAglassTM’ [2]. This unique electrical property shows that vanadate glass will be a good candidate for electrode of secondary batteries. In order to find a vanadate glass with higher , we have investigated several vanadate glasses. In the present study, we report a new conductive vanadate glass containing ZrO2 with high  value without HT. Experimental A new vanadate glass with the composition of xZrO2･ 10Fe2O3･(90−x)V2O5 (x=0-30), abbreviated as xZFV, was prepared by a conventional melt-quenching method under the melting temperature and time of 1200-1400 oC for 1h. For comparison, another vanadate glass with the composition of xZrO2･(20- x)CaO･10Fe2O3･70V2O5 (x=0-20), abbreviated as xZCFV, was prepared under the same condition. Isothermal heat treatment was performed at 500 oC for 100 min in air. 57Fe-Mössbauer spectra were measured by constant acceleration method. 57Co(Rh) and -Fe were used as a source and a reference, respectively. Measurements of  were carried out by DC four-probe method. Results and Discussion Two doublets with isomer shift () and quadrupole splitting () of 0.42±0.01 and 0.29±0.01 mm s-1, 0.34±0.03 and 1.48±0.06 mm s-1 were observed from the 57Fe- Mössbaeur spectrum of heat-treated 20ZFV glass, respectively of which is ascribed to FeIII2VV4O13 and an amorphous FeIII-VIV-O phases [3] (Fig. 1(a)). On the other hand, three paramagnetic doublets with and  of 0.39±0.01 and 0.33±0.04, 0.40±0.01 and 0.65±0.04, and 0.32±0.01 and 1.12±0.03 mm s-1 were observed from 0ZCFV glass (Fig. 1(b)), which is ascribed to FeIIIVVO4 [4]. These results may suggest that when a glass contained few network-modifiers (NWM), iron ion partially reduces vanadium from VV to VIV. (a) (b -4 -3 -2 -1 0 1 2 3 4 Velocity / mm-1s Figure 1. 57Fe-Mössbauer spectra of (a) 20ZFV and (b) 0ZCFV heated at 500 oC for 100min. A gradual increase in was observed from 6.3×10-5 to 2.9×10-3 S cm-1 with increasing ZrO2 content from 0 to 30 mol%. However, the drastic increase in due to HT, which could be observed in 0ZCFV, did not occur for xZFV glass. It is concluded that introduction of zirconia into vanadate glass results in higher conductivity without HT. In addition, we found that it is favorable for vanadate glass to contain less than 20 mol% of Ca2+ for the drastic increase in caused by HT. References [1] N.F. Mott, Adv. Phys. V. 16 No.61 (1967) 49 [2] T. Nishida, Jpn. Patent (2006) No. 3854985. [3] A. Brückner, G.-U. Wolf, M. Meisel, R. Stösser, H. Mehner, F. Majunke and M. Baerns, J. Catal. V. 154 (1995) 11 [4] S. Kubuki, K. Matsuda, K. Akiyama and T. Nishida, J. Radioanal. Nucl. Chem. V. 299 (2014) 453
  • 32.
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    T08‐ Magnetism andMagnetic Materials 29
  • 34.
    T08: CORRELATION BETWEENMILLING TIME OF POWDER, AND THE TEMPERATURE OF SUBSTRATE ON THE PROPERTIES OF NdFe THIN FILMS Y.A. Rojas Martínez, D. Oyola Lozano, H. Bustos Rodríguez Department of Physics, University of Tolima, A.A. 546, Ibagué, Colombia *Corresponding author: e-mail: yarojas@ut.edu.co Keywords: Mössbauer spectrometry, Thin films, Mechanical alloy Topic: T08- Magnetism and Magnetic Materials In this study we report the structural and magnetic properties, obtained by 57Fe Mössbauer spectrometry (MS) and X-ray diffraction (XRD), and Physical Properties Measurement System (PPMS), of amorphous rare-earth transition metal alloys of compositions Nd0.257Fe0.743 prepared by mechanical alloying during 12, 24, and 48 hours to study the influence of the milling time of powders. The films were prepared by DC sputtering technique deposited on Kapton substrate, at substrate temperature varying at 77°K,300°K, 450°K, To study the influence of the temperature substrate in their magnetic and structural properties. The X-rays results show that the α-Fe and amorphous phase in all the samples are present. The first decreases while the second one increase, with increase of the milling time and the substrate temperature, respectively. Mossbauer spectrometry results show that the amorphous phase in samples are ferromagnetic and appears as a hyperfine field distribution and a broad doublet. When the milling time and the substrate temperature increases, the paramagnetic contribution increase too. 30
  • 35.
    T08: IN γ-Fe2MnGaCOMPOUND DO Fe AND Mn ORDER MAGNETICALLY AT THE SAME TEMPERATURE? DO THEY COUPLE PARALLEL OR ANTIPARALLEL AT LOW TEMPERATURES? Edson Caetano Passamani Depto de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, ES, Brazil Heusler alloys (HAs) are generically represented by the stoichiometric X2YZ formula, where X and Y atoms are, in principle, d-elements with more than half-filled and less than half-filled shells, respectively and Z are atoms with sp-shell electrons. This series of compounds has potential for technological application including spintronics devices. They usually stabilize at room temperature, either with L21-type (Fm3m – number 225) full Heusler alloy (HA) or with C1b-type (F-43m) half-HA structure. Specifically, for the Fe2MnGa HA there are several controversies reported in literature; either related with its crystal structure or with its magnetic state at high and low temperatures (above 300 K and below 200 K). According to first principles calculations, Fe2MnGa HA should have the stable L21-type structure, as typically found in most of full HAs. However, it was recently reported the L12-type as its stable configuration, determined by electronic calculation. Experimental results seem also to be contradictory from the structural viewpoint because the samples are no single crystalline phase. From magnetic viewpoint, a ferromagnetic (FM) state is expected to be the ground state for the L21-type as well for the L12-type structure; a ferrimagnetic (FI) configuration is 0.02 eV high in energy. An additional controversy is related to the existence of exchange bias (EB) effect, which is attributed to an antiferromagnetic (AF) state that appears at low temperatures. However, there is no direct proof for a coexistence of FM and AF states in this material, except for the presence of the loop shifting effect at low temperatures. Then, as the γ-Fe2MnGa HA has iron as a natural constituent, 57Fe Mossbauer spectroscopy could be a suitable method to investigate Fe environment and its magnetic state, considering that Mn atoms govern the alloy magnetism. Thus, in this work, bulk and local magnetic properties of the single phase polycrystalline γ-Fe2MnGa Heusler alloy have been studied in a broad temperature range and under high applied magnetic fields using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. X-ray diffraction data of the γ-Fe2MnGa alloy indicate stabilization of a L12-type structure and no structural phase transformation induced by thermal effect. While magnetization experiments have shown that the Mn sublattice is ferromagnetic well above 300 K, 57Fe Mössbauer spectroscopy indicates that Fe-sublattice orders magnetically at 200 K and couple antiparallel with Mn sublattice. This ferrimagnetic state is responsible for the magnetization reduction in low temperatures observed at low temperature. Due to high magnetic anisotropy of this material, a large vertical (magnetization-axis) and horizontal (field-axis) magnetization loop shift effects are observed in field-cool process for fields up to 5T, consequently they cannot be purely attributed to the exchange bias effect, as reported in literature for this Heusler compound. 31
  • 36.
    T08: MAGNETIC PROPERTIESOF TWO CORE/SHELL NANOPARTICLES COUPLED VIA DIPOLAR INTERACTION W. R.Aguirre-Contreras1,*, and A.M. Schönhöbel1 1Grupo de Metalurgia y Transiciones de Fase, Facultad de Ciencias Naturales y Exactas, Universidad del Valle. Cali, Colombia *Corresponding author: e-mail: william.aguirre@correounivalle.edu.co Keywords: Magnetic core/shell nanoparticles, Monte Carlo simulation, Metropolis algorithm, dipolar interaction, Ising Model Topic: T08- Magnetism and Magnetic Materials We have used Monte Carlo simulations by Metropolis algorithm to study the magnetic properties of two identical core/shell nanoparticles with spherical shapes. A three-dimensional Ising Model with ferromagnetic (antiferromagnetic) nearest-neighbor couplings for core (shell) has been used on a body-centered cubic lattice and we have considered that nanoparticles are coupled by dipolar interactions. Zero-field cooling simulations were performed to obtain magnetization, susceptibility and Edward-Anderson factor as a function of dimensionless temperature. We also present the phase diagram as a function of the distance between nanoparticles and radii. References [1] A. Weizenmann and W. Figueiredo. Int. Journ. of Mod. Phys. C, V. 23(08) (2012) 1240006–1 [2] A. Weizenmann and W. Figueiredo. Phys. A, (2010) 389 [3] Liu W, Zhong W, Du YW., J. Nanosc. Nanotechnol. 8(6) (2008) 278 [4] D. Kechrakos and K. N. Trohidou. Appl. Phys. Lett. 81 (2002) 4574 32
  • 37.
    T08: MÖSSBAUER ANDSTRUCTURAL STUDY OF ALLOYS Fe1-XVX OBTAINED BY MECHANICAL ALLOYING Dagoberto Oyola Lozano, Yebrayl Antonio Rojas Martínez, Humberto Bustos Rodríguez 1Department of Physics, University of Tolima, A.A. 546, Ibagué, Colombia *Corresponding author: e-mail: doyola@ut.edu.co Keywords: Mechanical Alloying, Mössbauer Spectroscopy, Laves phase Topic: T08- Magnetism and Magnetic Materials In the present work we studied the structural and magnetic properties of milled powders to 12, 48 and 72 hours of the Fe1-xVx with x= 0.1, 0.3, 0.5 and 0.7 obtained by mechanical alloying. The samples were characterized by Mössbauer spectroscopy and, X-ray diffraction. For times all of milling results Mössbauer spectra reveal that the samples show a behavior paramagnetic for x>0.5, and its pattern of X-ray diffraction indicates the presence of the Fe, V and FeV phases. For times greater than 48 hours of milling Fe1-xVx system with x>0.7 tends to an amorphous structure. 33
  • 38.
    T08: MÖSSBAUER INVESTIGATIONSON THE DESORBTION OF HYDROGEN AND HYDROXYL FROM THE IRON OXIDE NANOPARTICLES L. Herojit Singh, S. S. Pati, A. C. de Oliveira and V. K. Garg Institute of Physics, University of Brasília, 70910-970 Brasília, DF, Brazil *Corresponding author: e-mail: loushambam@gmail.com Keywords: Mössbauer spectrum, reduction, topotactical transformation Topic: T08- Magnetism and Magnetic materials 34 Magnetite (Fe3O4) due to its unique magnetic properties, it plays an important role in biological applications such as hyperthermia, gene targeting etc. Stoichiometry of magnetite dictates the magnetism of magnetite. Iron oxide nanoparticles were synthesized through precipitation of FeSO4.7H2O in the presence of NaOH maintaining the pH value of 11. XRD of the as prepared nanoparticles confirmed the single phase formation of Fe3O4 having crystallite size of 60 nm as derived using Debye Scherer formula. Mössbauer spectra of the as prepared nanoparticles and after subsequent thermally treated at various temperatures at 10-6 mbar are depicted in Fig 1. These spectra could be resolved into four subspectra. (a) IS = 0.68 mm/s ,QS = 0.03 mm/s, absorption 47%, Hint = 453 kG corresponds to Octahedral site of Fe3O4 (b) IS = 0.29 mm/s ,QS = 0.03 mm/s, absorption 26 %, Hint = 488 kG corresponds to tetrahedral site of Fe3O4 (c) The third subspectra with an area of 4 % corresponds to goethite (α-FeOOH) and (d) the fourth component with 23 % area, Hint of 464 kG, QS = 0.14 mm/s and IS = 0.33 mm/s. corresponds to hematite (α-Fe2O3) The presence of hematite could not be observed by XRD, because thermal treatment altered the stoichiometry of Fe3O4 with fine nanoparticles. The heat treatment at 423K reduced the octahedral component to 37 % and the tetrahedral part increased to 38%. Surfaces with defects such as oxygen vacancies dissociates from H2O that came into contact into H+ and OH-that got adsorbed resulting to hydrogenated surface. The dissociated H+ and OH- could not recombine due to the Jahn-Teller distorted surface that could kinetically hinder recombinative desorption. Mild heat treatment desorbs the H+ and OH– driving away oxygen from the particles. Therefore the reduction of α-FeOOH to off-stoichiometric magnetite take place at 423 K and in the process some fraction of magnetite got oxidized leading to decrease of octahedral fraction by 10 %. However thermal treatment at 423 K is not sufficient to drive away oxygen from the non-cubic fraction and thus remains unchanged. Increase in thermal treatment temperature to 523 K reduces the non-cubic to off-stoichiometric magnetite. Fig1. Mössbauer spectra of the nanoparticles and the subsequent treated at various temperatures. Further increase in the temperature i.e. at 523 K reduces α-Fe2O3 and α-FeOOH to off-stoichiometric magnetite. The Mössbauer spectra of the nanoparticles after subjecting to 773 K are resolved into Fe3O4 and 13 % γ-Fe2O3. As the temperature increases from a 773 K temperature the H and OH are desorbed from the surface of the nanoparticles causing recombination resulting in diminution of the rate of reduction of the particles. Further increase in the temperature (above 873 K) the adsorbed H and OH no more acts as the reducing agent therefore topotactical transformation of α-FeOOH to α-Fe2O3 takes place and the α-Fe2O3 nucleates to larger particles experiencing the hyperfine field of a bulk α-Fe2O3. Acknowledgements: This work was supported by CAPES project A 127-2013; LHJ and SSP thankfully acknowledge post doctoral fellowships.
  • 39.
    T08: MÖSSBAUER STUDYOF ALLOYS Fe67.5Ni32.5, PREPARED BY ALLOY 35 Fe67.5Ni32.5 Fe67.5Ni32.5 without sieve -8 -6 -4 -2 0 2 4 6 8 1.00 0.98 0.96 0.94 1.01 1.00 0.99 0.98 0.97 0.96 1.00 0.98 0.96  m RT Mφssbauer spectra of the MA Fe67.5Ni32.5 samples milled for 10 h. relative transmission [%] relative transmission [%] m m Relative transmition [%] -8 -6 -4 -2 0 2 4 6 8 0.94 V[mm/s] MECHANICAL E.D. Benítez Rodríguez1, H. Bustos Rodriguez1, D. Oyola Lozano1, Y. A. Rojas Martínez1 y G.A. Pérez Alcázar2 1Department of Physics, University of Tolima, A.A. 546, Ibagué, Colombia 2) Instituto Nacional de Investigaciones Nucleares, Departamento de Química, Apdo. Postal 18-1027, Col. Escandón, Deleg. M. Hidalgo, C. P. 11801, México. D. F., México. *Corresponding author: e-mail: edbenitezr@ut.edu.co, hbustos@ut.edu.co Keywords: Mechanical alloying, X-Ray Diffraction, FeNi alloys, Mössbauer Spectrometry Topic: T08- Magnetism and Magnetic Materials We present the study Mössbauer of the system Fe67.5Ni32.5, prepared by mechanical alloying (MA). The structural, electronic and magnetic properties of alloys were analyzed using the techniques of x-ray diffraction (XRD), spectroscopy Mössbauer (MS) and PPMS (Physical Properties Measurement System), respectively. Samples are prepared with powders of iron and nickel in high purity (99.99%), is the respective stoichiometry of powders and powders in a planetary mill of high energy, alloy during a period of 10 hours with a 20: 1 ratio, from mass to mass of dust balls. Alloys are then sieved in different mesh: 18, 35, 60, 120, 230, 400 y 500 which are respectively equivalent a: 1mm, 500 μm, 250 μm, 125 μm, 63 μm, 38 μm y 25 μm. Mössbauer spectra in all alloys present a ferromagnetic behavior (see figure 1). In the graphs ZFC and FC, apparently exists in unscreened spin glass transition below 50K, which is reached to notice a bit in sample sizes between 63 and 125 micron and disappears for smaller sizes than 25 microns. This means that this phase is related to the larger particles. Besides the curve FC as low temperature is nearly constant for the first two and it may be due to magnetic dipole interaction is less intense for small particle as in this FC curve increases at low temperatures.
  • 40.
    T08: SPIN DYNAMICSIN COEXISTING ANTIFERROMAGNETIC AND SPINGLASS STATES OF MULTIFERROIC LEAD PEROVSKITES S. Chillal1, F.J. Litterst2,4 *, S.N. Gvasaliya1, T. Shaplygina3, S.G. Lushnikov3, J.A. Munevar4, E. Baggio Saitovitch4 and A. Zheludev1 1 ETH Zürich, Laboratory for Neutron Scattering and Magnetism, 8093 Zürich, Switzerland, 2 Technische Universität Braunschweig, 38106 Braunschweig, Germany.3 Ioffe Physical-Technical Institute RAS, 194021St.Petersburg, Russia. 4Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro, Brazil. *Corresponding author: e-mail: j.litterst@tu-bs.de Keywords: multiferroics, spin dynamics, perovskites, Mössbauer spectroscopy Topic:T08- Magnetism and Magnetic Materials 0.2 0.1 0.08 0.04 0.00 36 PbFe1/2Nb1/2O3 (PFN) and PbFe1/2Ta1/2O3 (PFT) belong to the family of PbB’xB’’1-xO3 perovskites which have inherent chemical disorder at the B-site. Due to this disorder, complex magnetic phase diagrams are expected in these materials that undergo ferroelectric transitions already above room temperature. Magnetic ground states ranging from simple antiferromagnetic to incommensurate structures have been reported [1]. As recently shown for PFN and PFT via macroscopic characterization, neutron scattering and 57Fe Mössbauer spectro-scopy, both compounds reveal antiferromagnetic transitions at 145 K and 153 K, respectively, followed by a spinglass transition around 10 K, below which antiferromagnetism coexists with a spinglass [2,3]. We suggest that the mechanism which is responsible for such a non-trivial ground state can be explained by a speromagnet-like spin arrangement (Fig. (1)). Figure 1. Schematic of the coexisting antiferromagnetic spinglass phase in the ground state of PFN and PFT. Mössbauer spectroscopy reveals strongly temperature dependent broadenings (Fig. (2a,b)) of magnetic hyperfine patterns. This may originate from dynamic mechanisms and some inhomogeneous broadening. Notably, there is found an unusual increase of the mean magnetic hyperfine field below 50 K (Fig. (2c)) that is accompanied by a decrease in the antiferromagnetic magnetic Bragg peak intensity as measured by neutron scattering (Fig. (2d)). This is indicative for the onset of magnetic freezing on the time scale of Mössbauer spectroscopy resembling earlier findings in re-entrant spinglass systems [4]. We shall present a coherent analysis of the spin dynamics and its temperature dependent development along the different magnetic regimes, as probed by 57Fe. 50 40 30 20 10 0 7500 5000 2500 Figure 2. a), b) The distribution of hyperfine fields in PbFe1/2Nb1/2O3 at 4K and 30K, c) temperature dependent mean magnetic hyperfine field at the Fe3+ ion as observed by Mössbauer spectro-scopy, d) AF Bragg peak intensity measured by neutron scattering at wave vector (½, ½, ½) References [1] G.A. Smolenskii and I.E. Chupis, Sov. Phys. Usp. 25 (1982) 475. [2] S. Chillal, et al., Phys. Rev. B 86 (2013) 220403R. [3] S. Chillal, et al., Phys. Rev. B 87 (2014) 174418. [4] R.A. Brand, et al., J. Phys. F 15 (1985) 1987, and references given there Fe3+ Nb5+ Φ 0 50 100 150 200 250 300 0 Temper ature (K) Intensity (a.u.) QAF=(1/2, 1/2, 1/2) <Bhf> (T) b d 0.0 -20 0 20 40 60 80 Probability 4 K Bhf (T) 30 K a) b) c) d)
  • 41.
    T08: STUDY OFSTRUCTURAL, OPTICAL AND MAGNETIC PROPERTIES OF Fe DOPED, Co DOPED, AND Fe-Co CO-DOPED ZnO J.J. Beltrán1*, J.A. Osorio1, C.A. Barrero1 and A. Punnoose2 1Grupo de Estado Sólido, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia 2 Department of Physics, Boise State University, Boise, Idaho 83725-1570, United States *Corresponding author: E-mail address: jjbj08@gmail.com Keywords: Diluted magnetic semiconductors, ZnO, Mössbauer spectra. Topic: T08-Magnetism and Materials Magnetic. Several works have reported ferromagnetic (FM) behavior in Fe doped, Co doped and Fe- Co co-doped ZnO systems, but there are a lot of controversies about the observed ferromagnetism. Then, careful structural and magnetic investigations with high quality single-phase 37 samples are desired to investigate in detail this controversy. In this work, we explore the effect of Fe doping, Zn1-xFexO, Co doping, Zn1-xCoxO and Fe-Co co-doping Zn1-xFexCoxO with x =0.0, 0.01, 0.03 and 0.05 on the crystallographic, structural, optical and magnetic properties of zinc oxide nanoparticles, prepared by Sol-Gel method. These fine powders of the as-obtained product, after being annealed at 550 oC for 1h, were characterized by X ray diffraction (XRD), optical absorption, X-ray photoelectronic spectroscopy (XPS), electron paramagnetic resonance (EPR) at RT and as a function of temperature, RT 57Fe Mössbauer spectroscopy and magnetic measurements as a function of applied magnetic field and as a function of temperature [1, 2]. The XRD patterns showed that the formation of hexagonal wurtzite ZnO crystal structure in all samples was discerned as the only single phase. Optical absorption results displayed that Co doped ZnO samples exhibited smaller band gaps (Eg) than Fe doped ZnO samples and that Fe-Co co-doped ZnO nanopowders showed intermediate values. In RT 57Fe Mössbauer spectra for all Zn1-xFexO samples only paramagnetic signals were detectable, ascribed to Fe3+. For x=0.05 the introduction of a third doublet was clearly necessary, which was attributed to spinel phase ZnFe2O4. In contrast, the spectra of Zn1-xFexCoxO sample did not show this third doublet, suggesting that Co ions might be preventing the formation of ZnFe2O4. XPS and EPR results showed only Co2+ ions for Zn1-xCoxO samples with x =0.01 and 0.03, and with further doping, mixed valence of Co2+ and Co3+ were evidenced, while in Fe-Co co-doped ZnO samples this mixed valence was observed for all doping concentration. Additionally, variable temperature EPR studies in Zn1- xFexCoxO suggested that some Co2+ ions are weakly FM coupled. Interestingly, pure ZnO sample exhibited very weak ferromagnetism, which might arise from the presence intrinsic defects that can become magnetic. The RT M vs H data of all doped and co-doped samples exhibited a linear component superimposed on a saturating FM-like magnetization. The FM character of Zn1-xFexO and Zn1-xCoxO were similar to each other, but increased compared with that of undoped ZnO. Now, Zn1-xFexCoxO samples showed higher FM behavior in comparison to the presence of only one of these cations. We deem that more probably the main role of Fe3+ ions in ZnO structure may be related to the formation of defects on the surface region, while Co ions have higher effect in its electronic properties. In Zn1-xFexCoxO the magnetic signal has been interpreted in terms of the charge transfer ferromagnetism involving mixed valence ions, most likely Co3+−Co2+ in addition to changes in the electronic structure associated with the presence of defects in the nanoparticles. The study suggested that the simultaneous introduction of Fe and Co ions in ZnO lattice has a strong synergistic effect because they eliminated the formation of the ZnFe2O4 and gave the strongest ferromagnetic signal in comparison to the presence of only one of these cations. References [1] J.J. Beltrán et.al J. Phys. Chem. C 118 (2014) 13203−13217. [2] J.J. Beltrán et.al J. Appl. Phys. 113 (2013) 17C308.
  • 42.
    T08: SYNTHESIS ANDCHARACTERIZATION OF NixCo1-xFe2O4 Nanoparticles P.M.A. Caetano1, P. R. Matos1, A. S. Albuquerque1, L.E. Fernadez-Outon2, J.D. Ardisson1 and W.A.A. Macedo1 1Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Serviço de Nanotecnologia, Belo Horizonte, Minas Gerais, Brasil. 2 Universidade Federal de Mina Gerais (UFMG), Departamento de Física, Belo Horizonte, Minas Gerais, Brasil. *Corresponding author: e-mail: patriciamacaetano@gmail.com Keywords: Ferrite, magnetism, nanostructure Topic: T08 - Magnetism and Magnetic Materials Nanostructured magnetic systems have been intensively investigated due to the different behavior of the materials at least one of their dimensions is in the nanometer range1. Among the nanostructured materials, ferrites, iron oxides of the type MFe2O4 (M = divalent metal ion) have been widely studied due to their magnetic properties, some of which are of great potential for application in the manufacturing of sensors with high sensitivity, e.g. for biomedical applications, such as hyperthermia, among others2,3. The present work consists in the synthesis and the investigation of structural and magnetic properties of nanostructured NixCo(1- x)Fe2O4 (with x = 0, 0.25, 0.5, 0.75 and 1.0) for hyperthermia applications. Ferrite nanoparticles were synthesized by coprecipitation and calcined at 700 °C, for 2 h. The nanoparticles were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy and vibrating sample magnetometry (VSM). The capacity of heat generation of the ferrites, dispersed in deionized water when submitted to an AC field (198 kHz and 220 Oe), was investigated. The XRD patterns, Fig.1 (a), showed well defined peaks, indicating the formation of the desired spinel phase. The average particle size was about 30 nm as calculated from Scherrer's formula. The magnetization curves showed that the coercivity and saturation magnetization increase due to the increase of cobalt content, as can be seen in Table 1. Table 1 – Saturation magnetization and coercivity of the ferrite samples Saturation magnetization (MSat) and Coercivity (Hc) NixCo1-xFe2O4 X=1 X=0.75 X=0.5 X=0.25 X=0 MSat (emu/g) 20 42 49 63 66 Hc (Oe) 150 490 920 1000 1413 38 (b) Figure 1 (a) XRD patterns and (b) Mössbauer spectra of ferrite samples studied. Mössbauer spectra of the ferrite samples, measured at 80 K, are shown in Fig.1 (b). The spectra were fitted with two sextets referring to the Fe3+ ions present in tetrahedral and octahedral sites. Samples with higher content of Ni showed significant heating, reaching temperatures higher than 50 oC after 30 min under an alternating magnetic field due to both Brownian motion and magnetisation reversal. Our results indicated that, the control of Ni and Co content, and the nanoparticle concentration, would allow for the tailoring of the heating capabilities of these ferrites being a promising material for several applications, such as hyperthermia. This work is supported by CAPES (PNPD), CNPq and FAPEMIG. References [1] Q.A. Pankhurst, J.Connolly, S.K. Jones, J. Dobson, J. Phys. D: Appl. Phys., 36, R167 (2003). [2] C.A. Sawyer, H. Habib, K. Miller, K.N. Collier, C.L. Ondeck, M.E. McHenry, J. Appl. Phys. 105, 07B320 (2009). [3] B. D. Cullity, Introduction to Magnetic Materials (Addison-Wesley, London, 1972).
  • 43.
    T08: SYNTHESIS OFSILVER -COATED MAGNETITE NANOCOMPOSITE FUNCTIONALIZED BY AZADIRACTHA INDICA J. L. López1, C. Carioca Fernandes1, D. M. Sá Oliveira1, M. Amorim Lima1, J. H. Dias Filho2, R. Paniago3 and K. Balzuweit3 1Centro de Ciências Biológicas e da Natureza, Núcleo de Física, Universidade Federal do Acre, Rio Branco, AC 69915-900, Brazil. 2) Departamento de Ciências Exatas, Universidade Estadual de Montes Claros, 39.401-089, Minas Gerais, Brazil. 3) Departamento de Física, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Brazil. *Corresponding author: e-mail: jorge0503@gmail.com Keywords: Nanoparticles,functionalization, Topic: T08- Magnetism and Magnetic Materials 39 Magnetic nanoparticles of iron oxides such as magnetite (Fe3O4) were coated with silver and then functionalized with extract of Azadirachta indica (Neem) forming a composite for use as non-toxic for the control of insect pests magnetic boots. The development of these composites requires a detailed study of the synthesis and magnetic properties of the functionalized nanoparticles to be used as an insecticide. In agriculture Azadirachta indica is used as a natural pesticide [1] and it was our interest to develop functionalized composite magnetic nanoparticles to combat Spodoptera frugiperda which is a pest of major importance in maize by reducing up to 34% crop productivity. This nanobiotechnological insecticide could also be applied to other type of pest. Magnetic fluids based on Fe3O4 has been synthesized using the condensation method by coprecipitating aqueous solutions of FeSO4, HCl and FeCl3, oleic acid mixtures in NaOH at room temperature [2-3]. Coating of Fe3O4 magnetic nanoparticles was achieved by dispersing this magnetite in AgNO3 solution containing specific amount of urea in vigorous stirring and mixture of sodium hydroxide solution and polyvinyl pyrrolidone (PVP), as stabilizer polymer, was added and finally a solution glucose was mixture. In the next step magnetite-silver core-shell nanoparticles were functionalized by Azadirachta indica. Samples with an average particle diameter ~7 nm and different concentrations of extract were studied by Mössbauer spectroscopy and dc magnetization measurements in the range of 4.2–250 K. The saturation magnetization (Ms) at 4.2 K were determined from M vs 1/H plots by extrapolating the value of magnetizations to infinite fields, to 3 - 5 emu/g and coercivity to 20- 50 Oe. The low saturation magnetization value was attributed to spin noncollinearity predominantly at the surface. From the magnetization measurements a magnetic anisotropy energy constant (K) between 1.3 - 3 ×104 J/m3 were calculated. Fe3O4 functionalized spectra at room temperature showed a singlet due to superparamagnetic relaxation and two sextets at low temperature. The line form in spectra Mössbauer vary with the temperatures it were simulated using a model of superparamagnetic relaxation of two levels (spin ½) and theory stochastic. It was taken into account that a distribution of the size of the particles that obeys a log-normal. References [1] A. H. Varella Bevilacqua H., B. Suffredini, M.M. Bernardi, Rev. Inst. Ciências da Saúde; 26(2) (2008)157. [2] J. L. López, J.H. Dias Filho, R. Paniago, H. – D. Pfannes, K. Balzuweit, Revista ECIPerú, 10(2) (2014) 5. [3] Y.M. Wang, X. Cao, G.H. Liu, R.Y. Hong, Y.M. Chen, X.F. Chen, H.Z. Li, B.Xu, D.G. Wei, J. Magn. Magn, Mater. 323 (2011) 2953.
  • 44.
    T09‐ Multilayers, ThinFilms and Artificially Structured Materials 40
  • 45.
    T10‐ Physical Metallurgyand Materials Science 41
  • 46.
    T10: MÖSSBAUER ANDXRD CHARACTERIZATION OF THE PHASE TRANSFORMATIONS IN A Fe-Mn-Al-C AS. CAST ALLOY DURING TRIBOLOGY TEST J. Ramos1, J. F. Piamba2, H. Sánchez3, and G.A. Pérez Alcázar2* 1Universidad Autónoma de Occidente, Km. 2 vía Jamundí, Cali, Colombia 2Universidad del Valle, Departamento Física, A.A. 25360, Cali, Colombia 3Universidad del Valle, Escuela de Materiales, A.A. 25360, Cali, Colombia *Corresponding author: e-mail: gpgeperez@gmail.com Keywords: Fermanal steels, DRX, Mossbauer spectrometry, tribology Topic: T10- Physical Metallurgy and Materials Science 42 In this study Fe-29Mn-6Al–0,9C-1,8Mo-1,6Si- 0,4Cu (%w) alloy was prepared in an induction furnace. Chemical analysis of the as-cast sample was performed by optical emission spectrometry; Pin on Disk Tribometer (ASTM G99) at room temperature was used to evaluate the mass loss. Microstructure was characterized by Optical Microscopy, Ray X Diffraction and Transmission Mossbauer Spectroscopy. The obtained microstructure of the as-cast sample is of dendritic type and its XRD pattern (not shown here) was refined with the lines of the austenite with a volumetric fraction of 99.39% and lattice parameter of 3.67 Å, and the lines of the martensite with a volumetric fraction of 0.61% and lattice parameters of 2.91 and 3.09 Å. 1,00 0,95 0,90 0,85 exp total fit1 -9 -6 -3 0 3 6 9 relative transmission V [mm/s] Figure 1. Mossbauer spectrum of the as-cast sample. Fig. 1 shows the Mossbauer spectrum of the as-cast sample and it was fitted with a singlet which corresponds to the austenite. After the tribology test, using a charge of 3N, the surface of the sample was examined and in Fig. 2 its XRD pattern is shown. The refinement of this pattern was performed with the lines of the austenite phase with a volumetric fraction of 97.89% and lattice parameter of 3.67 Å, and also the lines of the martensite with a volumetric fraction of 2.21% and lattices parameters of 2.90 and 3.09 Å. Figure 2. XRD pattern of the surface of the as-cast sample after the wear test. Finally Fig. 3 shows the Mossbauer spectrum of the surface of the as-cast sample after the wear test. 1,00 0,95 0,90 0,85 exp total fit1 fit2 fit3 fit4 fit5 -12 -9 -6 -3 0 3 6 9 12 relative transmission V [mm/s] Figure 3. Mossbauer spectra of the surface of the as-cast sample after the wear test This spectrum was fitted with a big paramagnetic site with similar parameters of that shown in Fig. 1, which corresponds to the austenite phase of Fe and a hyperfine magnetic field distribution which is associated to the disordered martensite which appear in the surface as a consequence of the wear process. The martensite is the responsible of the hardening of the material.
  • 47.
    T10: STRUCTURAL STUDYON Li2Fe1-xNixSiO4 J.A. Jaén1, M. Jiménez2, E. Flores3, A. Muñoz2, J.A. Tabares4, and G.A. Pérez Alcázar4 1Depto. de Química Física, CITEN, Edificio de Laboratorios Científicos-VIP, Universidad de Panamá, Panamá 2Depto. de Física, Universidad de Panamá, Panamá 3Escuela de Física, Universidad de Panamá, Panamá 4Departamento de Física, Universidad del Valle, AA 25360, Cali, Colombia *Corresponding author: e-mail: juan.jaen@up.ac.pa Keywords: Orthosilicates, Li2FeSiO4. Topic: T10- Physical Metallurgy and Materials Science Li2FeSiO4 is a promising cathode material for Li-ion 43 battery applications [1]. This material has good electrochemical activity and high cycling stability, but poor electronic conductivity and lithium ion mobility. One manner to improve the electrochemical performance is to dope with an isovalent cation [2-4]. Li2Fe1-xNixSiO4 (x=0, 0.10, 0.15, 0.20 and 0.30) samples were prepared via solid state reaction to study the effects of doping Ni on the crystal structure of the orthosilicate. The phase structure, morphology and composition of Li2Fe1-xNixSiO4 nanocrystals were investigated by X-ray diffraction (XRD), Mössbauer spectroscopy (MS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS), respectively. Mössbauer spectra are shown en Figure 1. X-ray diffraction data accompanied by Rietveld refinement and Mössbauer measurements showed that both, the pristine and doped Li2Fe1- xNixSiO4, basically crystallize in a monoclinic structure with (P21/n) symmetry. The doped materials up to 5% mol of Ni2+ retain the monoclinic structure and lattice parameter, which indicates that doping agent introduces into the structure of Li2FeSiO4 without destroying the lattice structure. There is a small increase of volume of the unit cell and slight changes in local environments around the FeO4 and SiO4 tetrahedra with increasing Ni doping. The crystallite size calculated from the Scherrer equation is about 60 nm. Some small amounts of electrochemical deleterious impurities, Fe2+ and Fe3+ phases, and unreacted Li2SiO3 are detected. Samples doped with more than 10 mol% contain some magnetic impurity of Fe-Ni alloy as a result of the reduction of the Fe2+ provided in the raw materials by residual carbon. The in situ formed carbon may enhance the electronic conductivity of the electrode, and effectively suppresses the grain growth of Li2FeSiO4 [5-7]. Magnetic measurements indicated that the lithium iron orthosilicate is a paramagnetic ceramic which becomes antiferromagnetic below 23 K. Nickel dopant does not modify the paramagnetic nature of this cathode material. Figure 1. Room temperature Mössbauer spectra of Li2Fe1-xNixSiO4 samples. References [1] A. Nytén, A. Abonimrane, M. Armand, T. Gustafsson and J.O. Thomas, Electrochem. Commun. 7 (2005), 156-160. [2] Y.H. Chen, Y.M. Zhao, X.N. An, J.M. Liu, Y.Z. Dong, Electrochim. Acta 54 (2009), 5844- 5850. [3] C. Deng, S. Zhang, S.Y. Yang, B.L. Fu and J. Ma, J. Power Sources 196 (2011), 386–392. [4] B. Shao and I. Taniguchi, J. Power Sources, 199 (2012) 278-286. [5] L.M. Li, H.J. Guo, X.H. Li, Z.X. Wang, W.J. Peng, K.X. Xiang and X. Cao, J. Power Sources 189 (2009), 45-50. [6] Z. Yan, S. Cai, L. Miao, X. Zhou and Y. Zhao, J. Alloys Compd. 511(1) (2012), 101-106. [7] Z. Yan, S. Cai, L. Miao, X. Zhou and Y. Zhao, J. Alloys Compd. 511(1) (2012), 101-106.
  • 48.
  • 49.
    T02 CHARACTERIZATION OFNATURAL ZEOLITE CLINOPTILOLITE FOR SORPTION OF 45 CONTAMINATNS E. Xingu-Contreras1, G. García-R1, I. García-Sosa2 and A. Cabral-Prieto2(*) 1Instituto Tecnológico de Toluca, Avenida Tecnológico S/N, Fraccionamiento. La Virgen, c. p. 52149, Metepec, Estado de México, México. 2) Instituto Nacional de Investigaciones Nucleares, Departamento de Química, Apdo. Postal 18-1027, Col. Escandón, Deleg. M. Hidalgo, C. P. 11801, México. D. F., México. *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: zeolites, nanomaterials, Móssbauer. Sorption. Topic: T02- Amorphous, nanocrystal ans nanoparticles Cd contaminated rivers is one of the ambient problems that society is facing since long time ago. The traditional chemical routines produce secondary to use procedures of green chemistry [1]. In this sense present study a Mexican pretreated natural zeolite, products that the environment is further contaminates. So, new methodologies are necessary to remediate these ambient problems by trying the Clinoptilolite, with adsorbed nano crystals of Fe0 is used to remove Cr(II) in aqueous phase. The characterization of this pretreated zeolitic material, before and after the sorption process was made using X-ray diffraction (XRD), Scanned electron microscopy (SEM/EDS) and Mössbauer spectroscopy. The XRD patterns of this zeolitic material are characteristic the Clinoptilolite zeolite only. Figure 1 XRD patterns of the treated Clinoptilolite. (a) Tarjeta JCPDS, (b) natural zeolite, (c) natural zeolite with Fe0 nanoparticles. From SEM, nano particles of different size were observed ranging from 8 to 120 nm. The Mössbauer spectra of these zeolite materials may consist of a well defined quadrupole double superimposed to broad magnetic pattern. From the isothermal curves of adsorption 35 mg of Cd(II) /g of natural zeolite can be removed from aqueous media. Figure 2. SEM image of the natural zeolite with nano particles of Fe0, prepared with 0.54 g of FeCl3 6 H2O per g of natural zeolite [2]. Figure 3. Typical Mössbauer spectrum of natural zeolite with Fe0 core-shell nano particles.
  • 50.
    The sorption ofCd(II) using natural zeolite alone removes 30 mg of Cd(II)/g, suggesting that iron nano particles may favor the removal of heavy metals more efficiently. References [1] Lázar, K., Beyer, H., Onyestyák, G., Jönsson, B., Varga, L., & Pronier, S. NanoStructured Materials, 12, (1999). 155- 158. [2] Yuvakkumar, R., Elango, V., Rajendran, V., & Kannan, N. Digest Journal of Nanomaterials and Biostructures", (2011). 1771-1776. 46
  • 51.
    T02 NOVEL PROTOCOLFOR THE SOLID‐STATE SYNTHESIS OF MAGNETITE FOR 1.000 0.995 0.990 0.985 0.980 -12 -9 -6 -3 0 3 6 9 12 Velocity (mm/s) -10 -5 0 5 10 Velocity (mm/s) 47 MEDICAL PRACTICES D.L. Paiva, A.L. Andrade, J.D. Fabris, J.D. Ardisson, and R.Z. Domingues 1Department of Chemistry CCEB, Federal University of Ouro Preto, 35400-000 Ouro Preto, Minas Gerais, Brazil. 2Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), 39100-000 Diamantina, Minas Gerais, Brazil. 3Laboratory of Applied Physics, Center for the Development of the Nuclear Technology, 31270-901 Belo Horizonte, Minas Gerais, Brazil. 4Department of Chemistry ICEx, Federal University of Minas Gerais (UFMG), 31270-901 Belo Horizonte, Minas Gerais, Brazil. *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: Biomedicine, Nanotechnology, Sucrose Topic: T02- Amorphous, Nanocrystals and Nanoparticles Real benefits of nanotechnology both in industrial processes and in medicine are being inimitable. Reducing sizes may significantly change some physical and chemical properties, including electrical conductivity, magnetic response, active surface area, chemical reactivity, and biological activity, relatively to the corresponding characteristics of the bulk counterpart material. The way nanoparticles are synthesized may determine their morphological uniformity, their particle sizes distribution and, as a critical feature for clinical purposes, their purity. These conditions become one of the key-issues for researchers in nanoscience and developers in nanotechnology, particularly to plan the synthesis of maghemite (-Fe2O3) or magnetite (Fe3O4) with controlled form, size in the nanoscale and magnetically induced hyperthermic behavior, if the material is to be destined to medical clinical practices. This work was devoted to the synthesis of magnetite nanoparticles by reducing the chemical oxidation state of iron (III) in a commercial synthetic maghemite. The direct solid-state chemical conversion procedure that was first used by Pereira [1] to obtain magnetite by mixing and burning a natural hematite (Fe2O3) with glucose was found unsuccessful, in the present case. Instead, the magnetite could only be effectively produced by putting the reacting mixture of the starting synthetic commercial maghemite mixed with sucrose in a furnace at 400 oC for 20 min. The after-reaction residual carbon was removed with an oxidant chemical agent to render the suitably pure magnetic oxide. The samples were characterized by Mössbauer spectroscopy; powder X-ray diffraction and Fourier transform infrared (FTIR). The 298 K-Mössbauer spectrum collected for the starting maghemite and the corresponding parameters are given in Figure 1 and Table 1. Figure 2 shows the spectrum and the corresponding parameters (Table 2) for the obtained magnetite by using a mass ratio maghemite:sucrose of 1:5. Relative transmission Figure 1. 298 K-Mössbauer spectrum for the starting commercial synthetic maghemite. Table 1: Hyperfine parameters of the fitted Mössbauer spectra recorded at 298 K. */mms-1 2/mms-1 Bhf/T RA/% 0.33 0.01 50.3 77 0.30 -0.06 48.8 13 1.0043 0.9960 0.9877 Relative transmission Figure 2. 298 K-Mössbauer spectra for the obtained magnetite after the calcinations of maghemite with sucrose.
  • 52.
    Table 2: Hyperfineparameters of the fitted Mössbauer spectra recorded at 298 K. */mms-1 2/mms-1 Bhf/T RA/% 0.65 0.04 45.9 64 0.27 -0.02 48.9 34 *Relative to Fe. Acknowledgements: Work supported by FAPEMIG and CNPq (Brazil). JDF is indebted to CAPES (Brazil) for granting his Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. Reference [1] Pereira, MC (2009) Preparação de novos catalisadores tipo Fenton heterogeneous à base de óxidos de ferro formados em litologia de itabirito. DSc thesis. UFMG, Brazil. In Portuguese. 48
  • 53.
    T02 MÖSSBAUER STUDIESOF POLYANILINE COATED MAGNETIC NANOPARTICLES J.C. Maciel1,2, A.A.D. 49 Merces2, M. Cabrera2, W.T. Shigeyosi3, S. D. de Souza4, M. Olzon-Dionysio4, C.A. Cardoso3 and L.B. Carvalho Jr.2 1Universidade Federal de Roraima, Boa Vista, RR, Brazil. 2Laboratório de Imunopatologia Keizo Asami, Universidade Federal de Pernambuco, Recife,PE, Brazil. 3Departamento de Física, Universidade Federal de São Carlos, São Carlos, SP, Brazil. 4 Universidade Federal dos Vales de Jequitinhonha e Mucuri, Diamantina, MG, Brazil *Corresponding author: e-mail: jackeline_maciel@hotmail.com Keywords: PANI, magnetic nanoparticles, magnetite Topic:T02- Amorphous, Nanocrystals and Nanoparticles Polyaniline (PANI) draws special attention among other conducting polymers due to the simple synthetic methodology, good environmental stability, optical activity, controllable doping [1], easy tunability of its electronic properties and high levels of electromagnetic shielding performances at microwave frequencies with a low mass by unit of surface [2]. The aim of this work is to study the structural and magnetic characteristics of polyaniline coated magnetic nanoparticles for their application as an insoluble support for enzyme immobilization. The differences in the crystalline behavior of magnetic nanoparticles and polyaniline coated magnetic nanoparticles (mPANI) are analyzed using XRD measurements. Fig. 1 shows XRD patterns for magnetic nanoparticles and mPANI. Figure 1. XRD patterns. The 2θ peaks at 18.44°, 30.30°, 35.67°, 43.37°, 53.80°, 57.35°, 62.97°, 71.43° and 74.48° are attributed to the crystal planes of magnetite. According to Yu et al. [3], the absence of the (221) reflections, corresponding to maghemite, suggests magnetite as a predominant phase. In this work, the absence of this peak was also observed. However, we cannot rule out the presence of maghemite in the samples produced, as the FTIR results, for example, suggest otherwise (Fig. 1). Fig. 2 shows the adjusted Mössbauer spectra at 298 K for magnetic nanoparticles and mPANI, where the contribution of two magnetic subspectra corresponds to Fe3+ in the tetrahedral position and [Fe3+/Fe2+] in the octahedral coordination in the spinel structure. Figure 2. Mössbauer spectra at room temperature. In Fig. 2, the presence of a doublet at the center of the spectrum can be observed. This doublet emanates from ferric iron in a non-spherical place, which perhaps comes from the rim of the iron oxide core. The Mössbauer spectrum could not be fitted with two discrete tetrahedral and octahedral sites along with a doublet because of the superposition of relaxing sextet and doublet patterns. To block the superparamagnetic relaxation effect, the Mössbauer spectrum should be recorded at a low temperature. According to Mössbauer spectra and the hyperfine parameters, it is clear that the process to obtain the mPANI does not interfere significantly with the nature of the oxide. However, a small percentage of maghemite must be present in the samples due to the oxidation process. References [1] K.R., Reddy et al., React. Funct. Polym., V (67) (2007) 943. [2] B., Belaabe et al., J. Alloy Compd., V(527) (2012) 137. [3] R.E., Vandenberghe et al., Hyperfine Interact., V(126) (2000) 247.
  • 54.
    T02 STRUCTURAL ANDMICROSTRUCTURAL CHARACTERIZATION OF THE AlFe NANOSTRUCTURED INTERMETALLIC OBTAINED BY MECHANICAL MILLING 50 R.Rocha Cabrera, M. Pillaca, C.V. Landauro, J. Quispe- Marcatoma Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima 14, Perú *Corresponding author: e-mail: jquispem@unmsm.edu.pe Keywords: Al-Fe system, nanostructuration. Topic: T2- Amorphous, Nanocrystals and Nanoparticles Nowadays, intermetallic AlFe alloys have taken attention of many researchers for their application in different branches of industry. This is due to the high corrosion resistance and low density of these systems [1]. In particular, AlFe alloys have interesting mechanical and magnetic properties, where the order or disorder in the sample is of crucial importance to define its physical behavior [2]. In this sense, the nanostructuration process gives us the possibility to change its structure and, consequently, manipulate the physical properties as function of the average grain size [3]. In the context described above, in the present work we investigate the structure and micro-structure of the nanostructured intermetallic AlFe (50 at.% Al). Solid samples were produced using the arc furnace technique under Ar-atmosphere. Subsequently, the alloys were thermally annealed at 600°C during 48 hours. The nanostructured samples were obtained by means of mechanical milling employing a high energy ball milling equipment (SPEX 8000). The obtained products were characterized by powder X-ray diffraction (XRD) and transmission Mössbauer spectroscopy (TMS). The XRD results indicate that the annealed solid samples can be indexed as a single AlFe phase. The sample milled up to 20 hours presents AlFe nano-grains with a solid solution of Al in Fe, i.e. Fe(Al). The results of TMS show that the local order around Fe sites is of the B2-type. References [1] V.N. Antonov, O.V. Krasovska, E.E. Krasovskii, Y.V. Kudryavtsev, V.V. Nemoshkalenko, B.Y. Yavorsy, Y.P. Lee and K.W. Kim, Phys. Condens. Matter 9,11227, (1997). [2] H. Wu, I. Baaker, Y. Liu, X. Wu and J. Cheng, Intermetallics 19, 1517, (2011). [1] C. Suryanayana., Prog. Matter. Sci., 46, 1 (2001).
  • 55.
    T03 CHARACTERIZATION OFPIGMENT FROM THE TAMBO COLORADO ARCHAEOLOGICAL SITE BY MÖSSBAUER SPECTROSCOPY -10 -5 0 5 10 Velocity ( mm s-1 ) 51 A. Trujillo, E. Zeballos- Velásquez, V. Wright, M. Mejía 1Laboratorio de Arqueometría, 2Laboratorio de Cristalografía Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos. Ap. Postal 14-0149. Lima, Perú. 3 Instituto Francés de Estudios Andinos, Avenida Arequipa 4500, Casilla 18-1217, Lima, Perú. *Corresponding author: aletruj70@gmail.com Keywords: Pigments, Mössbauer spectroscopy, X-Ray Diffractometry Topic: T03- Applicationsin Soils, Mineralogy, Geology, Cements and Archaeology. The Tambo Colorado archaeological site, located on the right bank of the Pisco Valley (290 Km South of Lima), is of importance because of its monumentality, colorful and the apparent good condition, features that make it attractive to different visitors and researchers. Most of the studies about this site have been directed to make architectural records, interpretations of the function and use of areas of the site, as well as its strategic importance during the Inca conquest; interpretations of the symbolic importance of the mural paintings of the site have also been made. However, these studies do not have been articulated integrally with descriptions and records of the site, so it is considered useful to carry out an investigation involving the analysis of the nature of the materials, as well as an adequate understanding of the state of conservation of its architecture [1]. In the present work are analyzed samples of pigments from the Tambo Colorado site, using Mössbauer Spectroscopy by transmission and x-ray diffractometry, in order to study the structure of these materials. In Figure 1 are shown the Mössbauer spectrum of the sample Tambo RN. In the study of pigments containing iron, Mössbauer Spectroscopy has proven to be a useful and sensitive tool to identify the presence of iron sites that differ from one another not only in its octahedral or tetrahedral coordination but also in small deviations from the ideal geometry, in addition to the differences in their chemical environments [2]. In this sense, this research will contribute to achieve these goals, because the conservation requires a critical approach based on the definition of the main characteristics of the object to be treated, which can be achieved with a qualitative and quantitative understanding of the physico-chemical properties of the object in study [3]. 1.005 1.000 0.995 0.990 0.985 0.980 0.975 0.970 0.965 Figure 1. Mossbauer spectrum of sample Tambo RN. Relative transmission (%) References [1] Wright V. Proyecto de Investigación Tambo Colorado. Instituto Francés de Estudios Andinos. Lima (2012). [2] U, Casellato; P, Vigato; U, Russo, M, Matteini, Journal of Cultural Heritage 1 (2000) 217-232. [3] D, Hradila; T, Grygara; J, Hradilova; P, Bezdicka.. Applied Clay Science 22 (2003) 223– 236.
  • 56.
    T03 CHEMICAL ANDMINERALOGICAL ANALYSES OF PIGMENTS FROM RUPESTRIAN PAINTINGS OF THE PEDRA DO CANTAGALO I SITE, IN PIAUÍ, BRAZIL 52 Luis Carlos Duarte Cavalcante1,2,3, Heralda Kelis Sousa Bezerra da Silva1, José Domingos Fabris2,3, José Domingos Ardisson4 1Centro de Ciências da Natureza, Universidade Federal do Piauí, 64049-550 Teresina, Piauí, Brazil 2Departamento de Química, Universidade Federal de Minas Gerais, 31270-020 Belo Horizonte, Minas Gerais, Brazil 3Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), 39100-000 Diamantina, Minas Gerais, Brazil 4Centro de Desenvolvimento da Tecnologia Nuclear, 31270-901 Belo Horizonte, Minas Gerais, Brazil *Corresponding author: e-mail: cavalcanteufpi@yahoo.com.br Keywords: Archaeometry, Mössbauer spectroscopy, rupestrian art. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The rupestrian art site known as Pedra do Cantagalo I (geographical coordinates, 04° 25’ 07.7” S 41° 40’ 20.2” W) is a sandstone shelter in a countryside area of the municipality of Piripiri, state of Piauí, Brazil. The archaeological site does contain an exceptional collection of more than 1,900 rupestrian paintings, rupestrian engravings, chipped lithics, polished lithics, ceramic materials and mineral pigments (reddish ochres). The rupestrian paintings mainly represent geometric graphisms, human handprints, anthropomorphic and zoomorphic motifs, painted in yellow, black, gray, white, orangish and red of different hues [1]. The chemical and mineralogical analyses of pigments from those rupestrian paintings were made in the laboratory with (i) energy dispersive X-ray fluorescence (EDXRF); (ii) room temperature 57Fe Mössbauer spectroscopy in backscattering geometry of -rays and (iii) grazing incidence X-ray diffraction (GIXRD), intending to identify the main iron-bearing minerals composing the painting pigments. Results reveal that the red pigments of the selected paintings are essentially composed of hematite (Fe2O3)-rich materials; the yellow pigments contain goethite (FeOOH) and the black are composed of carbon, which presumably were prepared as a mixture of charcoal and hematite, but maghemite (Fe2O3) is also clearly detected (Mössbauer spectrum, Figure 1). -10 -8 -6 -4 -2 0 2 4 6 8 10 1.08 1.07 1.06 1.05 1.04 1.03 1.02 1.01 1.00 Relative Emission Doppler Velocity, v/mm s-1 Figure 1. 57Fe Mössbauer spectrum of the pigment from the black rupestrian painting (sample PCI.2009.03). The iron oxides and oxyhydroxides occur in small particle sizes, with high isomorphic substitution of different cations for iron and low crystallinity. The X-ray diffraction patterns also reveal the occurrence of quartz (SiO4), brushite (CaPO3(OH).2H2O), gypsum (CaSO4.2H2O) and KAl3(SO4)2(OH)6 (Figure 2). QC 10 20 30 40 50 60 70 80 90 100 20 16 12 8 4 54 45 36 27 18 9 0 Substrate Intensity/102 Counts 2/º (CuK) Rupestrian Painting Q Q S S S GS GS GB GB GB CGM Q QC Q Q Q QG H H H HQM H H HM HG Figure 2. GIXRD patterns for the black rupestrian painting (PCI.2009.03) and its substrate. H = hematite, αFe2O3; M = maghemite, Fe2O3; C = carbon; Q = quartzo, SiO2; B = brushite, CaPO3(OH) . 2H2O; G = gypsum, CaSO4 . 2H2O; S = KAl3(SO4)2(OH)6. From these data, the precursor clayey material containing mainly hematite was somehow heated on wood fire, during manipulation to prepare the ochre. This hypothesis may explain the appearance of maghemite in the black painting.
  • 57.
    Reference [1] L.C. D. Cavalcante, A. A. Rodrigues. Int. J. South American Archaeology (7) (2010) 15. Acknowledgements: Work supported by FAPEMIG, FINEP, UFPI and CNPq (Brazil) (CNPq grants # 487148/2013-4; 124629/2013-0 and 305755-2013-7). JDF is indebted to CAPES (Brazil) for granting the Visiting Professorship at UFVJM under the PVNS program. The authors also thank Mr Mário da Silva Araújo Filho (CDTN) for his kind technical help on DRX data collection. 53
  • 58.
    T03 IN‐SITU 57FeMÖSSBAUER CHARACTERIZATION OF IRON OXIDES IN PIGMENTS OF A RUPESTRIAN PAINTING FROM THE SERRA DA CAPIVARA NATIONAL PARK, IN BRAZIL, WITH THE BACKSCATTERING MÖSSBAUER SPECTROMETER MIMOS II 54 Maria Conceição Soares Meneses Lage1, Luis Carlos Duarte Cavalcante1, Göstar Klingelhöfer2, José Domingos Fabris3,4,* 1Center of Natural Sciences; Federal University of Piauí (UFPI); 364049-550 Teresina; Piauí; Brazil. 2Institut Inorganic and Analytical Chemistry, Joh. Gutenberg-University Mainz. 55099 Mainz, Germany. 3Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM); PRPPG; Campus JK; 39100-00 Diamantina; Minas Gerais; Brazil. 4Department of Chemistry – ICEx; Federal University of Minas Gerais (UFMG); 31270-901 Belo Horizonte; Minas Gerais; Brazil. *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: Hematite, archaeological pigments, backscattering Mössbauer spectroscopy, MIMOS II, Serra da Capivara. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology Detailed stratigraphic and mineralogical descriptions of samples of pigment layers from prehistoric paintings of the Serra da Capivara National Park ¡Error! No se encuentra el origen de la referencia., in the southeast Piauí state, Brazil, were first reported on basis of chemical and mineralogical data obtained by various methods, including X-ray fluorescence spectroscopy, infrared spectroscopy, X-ray diffraction and scanning electron microscopy. From those analyzes, we know that the red pigments are mainly composed of hematite (α-Fe2O3); the yellow does contain mainly goethite (α-FeOOH); the white, gypsum (CaSO4.2H2O) or kaolinite (Al2Si2O5(OH)4); the grey is a mixture of kaolinite and hematite, and the black is derived from coal burning parts of animal carcasses. In more recent works, we used the miniaturized portable 57Fe Mössbauer backscattering spectrometer MIMOS II ¡Error! No se encuentra el origen de la referencia. to perform in situ measurements in the archaeological site known as Toca do Boqueirão do Sítio da Pedra Furada (BPF) ¡Error! No se encuentra el origen de la referencia., in order to specifically examine shades of dark red (Munsell color, 10R 3/3; reddish brown ¡Error! No se encuentra el origen de la referencia.) pigments and compare their differences relatively to the light red (10R 5/8; red) part of the same painting. The hyperfine Mössbauer parameters reveal that the dark red pigment (spectrum, Figure 1) is composed of two populations of well-crystalline hematite and very likely of a small proportion of maghemite (-Fe2O3), whereas the distinctly pigments of the pale-red portion of the painting exhibit a relatively less crystalline hematite mixed with a (super)paramagnetic Fe3+ (probably, also hematite in very small particles or paramagnetic iron in the structure of silicates). The corresponding analysis of the collected red ochre (the piece that was assumed to have been used to paint the archaeological panel) has also shown hematite and, in this case, a much larger proportion of maghemite, suggesting the possibility that the preparation of the pigment might have involved heating the mineralogical clay precursor somehow mixed with charcoal to prepare the prehistoric pigments. -10 -8 -6 -4 -2 0 2 4 6 8 10 1.011 1.008 1.005 1.002 0.999 Relative Emission Doppler Velocity, v/mm s-1 Figure 2. 57Fe Mössbauer spectrum of the dark red area of the rupestrian painting. Acknowledgements: Work supported by FAPEMIG and CNPq (Brazil). Authors thank Cecília Aparecida Lima and Anna Carolina Ferreira Borges, undergraduate students at UFPI, for their help on the field works. JDF is indebted to CAPES (Brazil) for granting the Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. References M.C.S.M. Lage, Étude archéométrique de I'art rupestre du sud-est du Piauí – Brésil. Université de Paris I, Panthéon – Sorbonne (1990) PhD thesis. 407p. G. Klingelhöfer et. al., Journal Geophysical Research 108 (E12) (2003) 8067-8084. N. Guidon and G. Delibrias, Nature V. 321 (1986) 769-771.
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    T03 IRON‐CONTAINING PIGMENTFROM A RUPESTRIAN PAINTING OF THE 55 PLANALTO TRADITION IN MINAS GERAIS, BRAZIL D. L. Floresta1,4, M. Fagundes2, J. D. Fabris2,3 and J. D. Ardisson4 1Instituto Federal Minas Gerais (IFMG), campus Santa Luzia, Santa Luzia, Minas Gerais, Brazil 2Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, Brazil 3Departamento de Química-ICEx, UFMG. Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil. 4Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, Minas Gerais, Brazil *Corresponding author: e-mail: denise.floresta@ifmg.edu.br Keywords: rock art, archaeometry, iron oxides Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology Archaeological rupestrian arts are of relatively spread occurrence all over the land area of the state of Minas Gerais (MG), Brazil. The archaeological Planalto Tradition is characterized by monochromic figures, especially in red or orange color, representing zoomorphic figures, particularly of cervids1,2. A fragment of a rock wall containing an archaeological painting identified as being of the Planalto Tradition was found at the site known as Itanguá, in the municipality of Senador Modestino Gonçalves (17o 49’ 41.51’’ S 43o 12’ 48.39’’ W), MG. The rock piece was collected by researchers of the Laboratory of the Archaeology and Landscape Studies of the Federal University of Valleys of Jequitinhonha and Mucuri, in Diamantina, also in MG. The painting itself is predominantly red, dark or even orange in color, but no defined shape could be clearly identified. A small subsample was cut out from the sampled rock-fragment and analyzed by conversion electron Mössbauer spectroscopy (CEMS) at room temperature (298 K). The obtained spectrum and corresponding fitted parameters are in Fig. 1 and Table 1, respectively. Results reveal that hematite (Fe2O3) is the magnetically ordered iron oxide. A (super)paramagnetic ferric component with relative spectral area RA = 64 % also appears in the Mössbauer pattern3. Figure 1- Spectrum Mössbauer and first adjust of CEMS analyses of a rock painting fragment, at room temperature. Table 1- 298 K-Mössbauer hyperfine parameters from the CEMS analysis of pigments of an archaeological rock-painting fragment.  = isomer shift relative to the Fe;  = quadrupole splitting;  = quadrupole shift; Bhf = hyperfine Field and RA = relative subspectral area. Site  ,  Bhf RA mm/s mm/s tesla % Fe2O3 0.31 -0.28 51.5 36 Fe3+ 0.40 0.67 64 The quantitative chemical analysis of the pigment on this rock fragment was made by X-ray fluorescence. The chemical composition is rather comparable for both dark red and orange pigments: the dusky region of the painting area was found to contain only ˜5 mass% more of iron than the orange area. Results from further analyses, which are currently being made, including Mössbauer measurements at low temperatures to check for the supeperamagnetic behavior, but also with grazing incidence X-ray diffraction (GIXRD) and scanning electron microscope (SEM), will be presented. References [1] V.L. Salvio (2007) MS thesis, UFMG, Brazil. 119 p. [2] R.L.S Aguiar, K.M. Lima and L. G. Freitas. Diálogos (Maringá Online) v. 16 (2012) 1026. [3] A. Kuno, M. Matsuo, A. Pascual Soto, and K. Tsukamoto. Hyp. Interact. V. 156/157 (2004) 431. Acknowledgments Work financially supported by CNPq and FAPEMIG. CAPES (Brazil) grants the visiting professorship to JDF, under the PVNS program, at UFVJM. This ongoing study is part of the PhD thesis by DLF at CDTN; her work is formally and institutionally supported by the IFMG.
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    T03 KINETICS OFMETEORITIC Fe50Ni50 SUPERSTRUCTURE ORDER‐DISORDER 300°C 400 °C 450 °C 475 °C 500 °C 550 °C 600 °C 1 10 100 1000 10000 100000 1000000 Cumulative annealing time (min) 56 PROCESS E. Dos Santos, J. Gattacceca, P. Rochette and R. B. Scorzelli 1Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Rio de Janeiro, 22290-180, Brazil. 2Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement, UM34, CNRS/Aix-Marseille University, 1345 Aix-en-Provence, France. *Corresponding author: e-mail: edisanfi@cbpf.br Keywords: Tetrataenite, Meteorite, Apparent Curie temperature Topic: T03 – Applications in Soils, Mineralogy, Geology, Cements and Archaeology Tetrataenite is a chemically ordered L10-type Fe50Ni50 alloy detected for the first time by 57Fe Mössbauer studies in iron meteorites [1]. Because tetrataenite has very high coercivity compared to other FeNi metallic minerals found in meteorites, its presence is a proxy to the thermal history of meteorites [2]. In particular, it is a sensitive tracer of transient secondary thermal events, like those associated with impacts, that leads to disordering of tetrataenite into taenite. However, in the absence of data about the time-temperature conditions necessary to disorder tetrataenite, it is currently impossible to interpret quantitatively such observations. Several works show that thermomagnetic curves for tetrataenite are essentially flat in a temperature range below 500 °C, and drop sharply at ~ 550 °C (the apparent Curie point), although no information was provided about the heating rate [3]. At the apparent Curie point disordering takes place and tetrataenite is transformed into taenite. Thus, in order to gain insights related to the disordering kinetics of tetrataenite, we present results concerning time-temperature experiments for tetrataenite disordering, using Santa Catharina meteorite as a starting material, and magnetic properties as a proxy to the ordered state. Santa Catharina meteorite is known to contain about 50% tetrataenite [4]. Samples of about 5 mg were annealed in air, at temperatures in the 300 to 600 °C range. Annealing was carried out in several cycles ranging from 3 min to more than 10 days, followed by cooling to room temperature. Before and after each annealing step hysteresis properties were measured. At annealing temperatures below the chemical order-disorder transition temperature (~ 320 °C, [5]), no changes in magnetic properties were observed. Indeed, our results show that coercivity of remanence (BCR) remains constant after annealing experiments at 300 °C for over 6 days, indicating that magnetocrystalline anisotropy responsible for the high coercivity of tetrataenite is stable. Nevertheless, ~30 days are necessary at 400 °C to decrease BCR by about 50%, whereas annealing at 550 °C and 600 °C for ~ 10 min and ~ 3 min, respectively, decreases BCR by more than 90%, as shown in Fig. (1). 450 400 350 300 250 200 150 100 50 0 BCR (mT) Figure 1. Coercivity of remanence (BCR) vs annealing time for Santa Catharina meteorite. This data set allows to propose a quantitative time-temperature scenario to account for the disordering of tetrataenite in some meteorites. It was shown that tetrataenite disordering may take place at any temperature above the order-disorder transition for L10 superstructure phase when the appropriate time-scale is considered. Therefore the apparent Curie point for tetrataenite is not an absolute property in the sense that any estimate of this parameter should be referred to a given time-scale. Thus, we argue that the apparent Curie point estimated in previous works does not give a complete picture of tetrataenite disordering. References [1] J. F. Petersen, M. Aydin and J. M. Knudsen. Phys. Lett. V. 62 (3) (1977) 192. [2] J. Gattacceca, C. Suavet, P. Rochette, B. P. Weiss, M. Winklhofer, M. Uehara and J. M. Friedrich. Met. Planet. Sci. V. 49 (4) (2014) 652. [3] T. Nagata, J. A. Danon and M. Funaki. Mem. Natl. Inst. Polar Res., Spec. Issue V. 46 (1987) 263. [4] J. Danon, R. B. Scorzelli, I. Souza Azevedo, J. Laugier and A. Chamberod. Nature V. 284 (1980) 537. [5] J. Pauleve, D. Dautreppe, J. Laugier and L. Néel. J. Phys. Radium V. 23 (10) (1962) 841.
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    T03 MÖSSBAUER ANDRAMAN SPECTROSCOPY OF CONCRETES USED IN THE 40 38 36 34 32 30 28 26 24 22 20 18 16 14 Dose (KGy) Ca4Al2Fe2O10 CON APASCO < 15mm CON CRUZ AZUL CON IMPER Ca3A lO6 The highest compression strength was obtained in the concrete specimen prepared with EXTRA CEMEX irradiated at 10000 kGy. Tricalcium aluminate (C3A) and tetracalcium alumnoferrite (C4AF) are main phases in cements (Fig. 2b). Iron in C4AF is bivalent (Fe2+) and trivalent (Fe3+) with the latter being in tetrahedral (T) and octahedral (O) coordinations [3]. Iron in our cements (see figure. 1a) are in trivalente state (Fe3+), distributed in two tetrahedral positions (T1) and (T2), the Fe2+ is part of the raw material (grave). EXTRA 57 CONDITINING SPENT RADIOACTIVE SOURCE F. Monroy Guzman1, M. González Neri1, 2, R. C. González Díaz1, G. Ortíz Arcivar1, I. J. Corona Pérez1, N. Nava, A.Cabral-Prieto1, L. Escobar1 1 Instituto Nacional de Investigaciones Nucleares. Carretera México-Toluca s/n, La Marquesa, Ocoyoacac, Edo. de México, C. P. 52750, México 2 Universidad Mexiquense del Bicentenario Unidad Lerma, Parque Industrial Automotriz Ex Hacienda Doña Rosa, Lerma Edo. México *Corresponding author: e-mail: fabiola.monroy@inin.gob.mx Keywords: concrete, Rama, radioactive sources Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archeology Around 8189 spent sealed radioactive sources (Am-241, Ir-192, Ra-226, Cs-137, Co-60, Sr-90, Po-210, Th-230, etc.), generated in Mexico, have been immobilized in concrete at ININ. The concretes used in the immobilization of these sources have not yet been standardized and characterized, however they must to comply with NOM-0019-NUCL-1995 [1,2]. Therefore, concrete specimens were prepared from four types of Portland cements: CPC 30RS EXTRA CEMEX, CPC 30R IMPER CEMEX, CPC 30RS APASCO, and CPC 30R CRUZ AZUL (manufactured in Mexico), using three particle sizes of the coarse aggregate (grave) (> 30 mm, 30-15 mm and <15mm). Concrete specimens were subjected to compression strength, -ray irradiation and thermal resistance assays; and characterized by using Mössbauer and Raman Spectroscopy, in order to correlate the effects of irradiation doses, thermal treatments, and compressive strengths with the oxidation states of iron. The compressive strengths of all concrete test specimens were between 30 and 50 times higher than the required by the NOM- 0019-NUCL-1995, (> 0.35 MPa) as shown in figure 1. Figure 1. Compression strenght of concrete test specimens as a function of radiation dose and thermal treatment and Raman Spectra IMPER CRUZ APASCO APASCO >30 APASCO <15 CONCRETES 12 COMPRESSION STRENGTH (Mpa) 0 200 400 600 1000 10000 THERMAL 200 300 400 500 600 700 Raman shift cm-1 CON EXTRA Ca3AlO6
  • 62.
    1.001 1.000 0.999 0.998 0.997 0.996 0.995 0.994 EXTRA CEMEX CEMENT CONCRETE EXTRA CEMEX CONCRETE EXTRA CEMEX 200 kGy CONCRETE EXTRA CEMEX 400 kGy (a) (b) 1.000 0.995 Figure 2 Mössbauer spectra of (a) cements and raw materials (grave and sand), and a (b) -ray irradiated concrete. A discussion of the -ray irradiated concrete will be given. Generally speaking there is an oxidation (red)/reduction(blue) process of the Fe2+. The octahedral sites of Fe3+ in the original cement move to tetrahedral sites when the concrete is formed. References [1] J.Jiménez Dominguez Acondicionamiento de fuentes selladas gastadas. P.DR (PATRADER)-31, ININ, México, 2009. [2] NOM-019-NUCL-1995. Diario Oficial, Secretaría de Energía, México, 14 agosto 1996. [3] V. Lilkov, O. Petrov, Y. Tzvetanova, P. Savov, Construction and Building Materials 29 (2013) 33-42. 58 -4 -3 -2 -1 0 1 2 3 4 0.990 sand grave EXTRA CEMEX IMPER CEMEX CRUZ AZUL APASCO Transmission Velocity mm/s -4 -2 0 2 4 0.993 Transmission Velocity (mm/s)
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    T03 MÖSSBAUER ANDX‐RAY DIFFRACTION STUDY OF ARCHAEOLOGICAL 59 CERAMICS FROM SÃO LUIZ DO MARANHÃO P. Munayco, E. Dos Santos, R.B. Scorzelli, R.A. Ikeoka and C.R. Appoloni 1Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150 - Urca, CEP: 22290-180, Rio de Janeiro, RJ – Brazil. 2 Instituto de Física, Universidade Federal de Mato Grosso, Av. Fernando Corrêa Costa, 2367, Cuiabá, Mato Grosso, Brazil. 3 Departamento de Física/CCE, Universidade Estadual de Londrina; Cx.Postal 6001,CEP 86051-990 Londrina/PR – Brazil. *Corresponding author: e-mail: mpablo@cbpf.br Keywords: Archaeological ceramics, Firing temperature, Mössbauer, XRD Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The study of cultural heritage of ancient people is essential in building the memory of any society. This knowledge may be acquired by archaeological research. Among such cultural material, ceramics are highlighted as objects of highly archeological value because they are extremely resistant to weather and environment conditions. The chemical characterization of such fragments may provide important information about the origin of the raw material, the manufacture process, the quality of the coating, indexes of the occurrence of paintings, etc., This work deals with ceramic fragments from the Sambaquis of “Panaquatira” and “Rabo de Porco” located in the São Luiz city area, Brazilian northeast. Ancient civilizations that inhabited that territory were characterized as fishing, catchers, hunters and ceramists populations. Dates obtained by termoluminescence ranged from 5730 to 127 BP. The ceramic fragments were analyzed by 57Fe Mössbauer spectroscopy and X-ray diffraction. The Mössbauer spectra of the samples from Panaquatira and Rabo de Porco were performed at room temperature, and, in a few selected cases, at low temperature in order to distinguish between paramagnetic phases and phases that are superparamagnetic at RT. The 57Fe Mössbauer spectra, from outer and inner portions of ceramic, evidenced the presence of one quadrupole doublet associated with the presence of Fe3+ species and one magnetic component associated with hematite. The inner portions show additionally one doublet associated to Fe2+ species. These results suggest that different atmospheres prevailed during the firing of the studied samples [1]. The quadrupole splitting (QS) of the paramagnetic Fe3+ component at room temperature obtained for the archaeological fragments, is used to determine its firing temperature by comparing it with clays, collected near the archaeological sites, fired in different temperatures, in the laboratory. The QS of the Fe3+ species measured at RT after refiring specimens of the archaeological pottery in air at increasing temperatures are compared with data obtained after firing clay under the same conditions. The QS for Fe3+ species in the refiring curve meets the firing curve of the clay at about 800 - 900 oC [2]. The XRD diffractograms of fragments from Panaquatira exhibit quartz, feldspars and layer silicates. Samples from Rabo de Porco show additionally mica and amphiboles suggesting a manufacturing process different from that employed in Panaquatira samples. References [1] P. Munayco, R.B Scorzelli, Hyperfine Interact. V. 222 (2013) S69. [2] C.R. Appoloni, R.A Ikeoka, O.H. Marcori, F. Lopes, M. A Rizzutto, J. F. Curado, R. B. Scorzelli, P. Munayco and A. M. Bandeira. International Symposium on Archaeometry (ISA), Los Angeles (2014).
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    T03 PROPERTIES MINERALOGICAL,STRUCTURAL AND ELECTRONIC PROPERTIES OF SOIL SAMPLES DISORIENTED CULTIVATED WITH SUGAR CANE USING ANALYSIS: PHYSICAL‐CHEMICAL, X‐RAY DIFFRACTION (XRD) AND MÖSSBAUER SPECTROMETRY (MS) 1.00 0.95 0.90 60 F. M. Vargas Fontalvo, H. Bustos Rodríguez, D. Oyola Lozano, Y.A. Rojas Martínez, E.A. Ávila Pedraza and G.A. Pérez Alcázar 1Universidad del Tolima. Grupo Ciencia de Materiales y Tecnología en Plasma, A.A.546, Ibagué, Colombia. 2) Universidad del Valle. Grupo Metalurgia Física y Teoría de las Transiciones de Fase, A.A.25360, Cali, Colombia * fmvargasf@ut.edu.co Keywords: Mössbauer spectrometry, agricultural soils, XRD. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The Mössbauer spectrometry (EM) of the 57Fe have been going on for several years now and has gained in importance as the information provided, in many cases, is not obtained by other techniques, in the last few decades numerous studies of soils [ 1-13] and in other fields has been implemented the combination of the Mössbauer spectrometry (EM) and X-ray diffraction (XRD) getting fruitful results) [ 14]. Sugar cane is the agricultural product of greater importance in the Valle del Cauca, Colombia, because of its impact socio-cultural and economic in the entire region, and will therefore take importance the study of the structural and electronic properties, samples of cultivated soils with sugar cane in that region, were applied multiple techniques aimed at the detection of phases present, calculations of hyperfine constants and structural properties, visualization and quantification of phases present with content, mainly of Fe+2 and Fe+3. We present a study of the mineralogy of disoriented samples of agricultural soils of different areas where sugar cane is grown in the department of Valle, using techniques of physical and chemical analysis of soils, XRD and MS. The physico-chemical characteristics of the soil, show the degree of alkalinity and texture through the measurement of chemical parameters such as pH, the percentage of organic matter and elements such as P, Ca, Mg, Na, K, Fe, Cu, Zn, Mn, B and S. also introducing the percentages of sand, silt and clay that characterize the parameters of texture. The Mössbauer spectrometry (MS) of Fe57 is being posted for several years to the study of soils and has gained importance as the information provided, in many cases, is not obtained by other techniques. Particularly the Mössbauer spectra of the samples analyzed soils of sugar cane crops show, at room temperature, the presence of mineral phases with content of Fe+2 and Fe+3. Using programs of refinement MOSFIT [16] we got the respective hyperfine parameters and comparing with Mössbauer Handbook [ 17], we identified phases as goethite, illite, kaolinite, montmorillonite and pyrite. Using XRD, mineral phases were identified with content of iron (Fe) as illite, biotite, and nontronite ferriphologopite and also the presence of other phases without content of iron (Fe) as quartz and andesine. Figure 1. illustrates the Mössbauer spectra at room temperature for two (2) soil samples sugar bowl del Valle del Cauca, Colombia, paramagnetic doublets are observed in all the spectra, which indicates mineral phases with the presence of the mineral of iron (Fe) belonging to Fe+2 and Fe+3. The parameters of the electronic content of phases with iron (Fe), such as the diversion isomeric, cleavage and field cuadrupolar hyperfine were found using the Mössbauer spectrometry Table. (2). 1.00 0.98 0.96 Sample FR57 Exp Total Fe+2 Fe+3 Fe+3 -9 -6 -3 0 3 6 9 Today's date is 09/08/14 The Document name is: ".opj, importp" relative transmission V [mm/s] (a) Exp Total Fe+2 Fe+3 Fe+3 Sample FR47 -9 -6 -3 0 3 6 9 Today's date is 09/08/14 The Document name is: ".opj, importp" relative transmission V [mm/s] (b) Figure 1. Setting Mössbauer spectra Agricultural soils cultivated with sugar cane in the department of Valle del Cauca and northern Cauca. In the analysis of the minerals from the soil samples of the cultivation of sugar cane by Mössbauer spectrometry mineral phases are determined with the presence of the mineral of iron (Fe) belonging to Fe+2 and Fe+3. We reaffirm that (MS) is a complementary tool and valid for the analysis of electronic properties of mineral samples of agricultural soils. References [1] Humberto Bustos Rodríguez, Dagoberto Oyola Lozano, Yebrayl A. Rojas Martínez, Marlene Rivera Pinilla and Germán A. Pérez Alcázar. Characterization of mineral phases of agricultural soil samples of Colombian coffee using Mössbauer spectroscopy and X-ray diffraction. Hyperfine Interact (2012) 208:13-18.
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    [2] S.P. Tanejaaand D. Rajb. Mössbauer and X-ray studies of soils. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. Volume 76, Issues 1-4, 4 April 1993, Pages 233-235. [3] Cerón Loayza, María Luisa. Estudio mineralógico de suelos agrícolas por espectroscopia Mössbauer. Tesis de Maestría. UNBA. 2001. [4] Ana E. Mijovilovich. Estudio Mössbauer de óxidos e hidróxidos de Fe: Aplicación al estudio de suelos. Tesis Doctoral. UNBA. 1997. [5] A. E. Mijovilovich, H. Morras, H. Causevic, C. Sarago-vi, Hyp. Int., 122. 199, pp. 83-85. [6] H.P. Gunnlaugsson, H. Rasmussen, M.B. Madsen, P. Nørnberg. New analysis of the Mössbauer spectra of olivine basalt rocks from Gusev crater on Mars. Planetary and Space Science 57 (2009) 640–645. [7] Claudia Hidalgo, Jorge D. Etchevers, Antonio Martínez-Richa, Hernani Yee-Madeira, Héctor A. Calderon, Ricardo Vera-Graziano, Francisco Matus. Mineralogical characterization of the fine fraction (b2 μm) of degraded volcanic soils and tepetates in Mexico. Applied Clay Science (2009). [8] Luke J. Kirwan, Francis A. Deeney, Gerard M. Croke, Kieran Hodnett. Characterization of various Jamaican bauxite ores by quantitative Rietveld X-ray powder diffraction and 57Fe Mössbauer spectroscopy. Int. J. Miner. Process. 91 (2009) 14–18. [9] Bustos Rodríguez Humberto. Estudio de propiedades electrónicas y estructurales de muestras minerales de menas auríferas colombianas, mediante el uso de microscopia óptica, espectrometría Mossbauer, difracción de rayos-x, SIMS y LAM-ICP-MS. Ph. D. Physical Sciences Tesis. Universidad del Valle (2006). [10] H. Bustos Rodríguez, Y. Rojas Martínez, D. Oyola Lozano, G.A. Pérez Alcázar, M. Fajardo, J. Mojica and J. C. Molano. Hyp. Int. (2005)161:61-68. [11] H. Bustos Rodríguez, D. Oyola Lozano, Y. A. Rojas Martínez, G.A. Pérez Alcázar A. G. Balogh. Invisible gold in Colombian auriferous soils. Hyp. Int. (2005) 166:605–611. [12] Humberto Bustos Rodríguez, Dagoberto Oyola Lozano, Yebrayl A. Rojas Martínez, Germán A. Pérez Alcázar, Stefan Flege, Adam G. Balogh, Louis J. Cabri, Michael Tubrett. Mineralogical analysis of auriferous ores from the El Diamante mine, Colombia. Hyp. Int. (2007) 175:195-206. [13] J. J. Ipus, J. Mojica* y G.A. Pérez Alcázar. Caracterización de arcillas colombianas por espectroscopia Mössbauer y difracción de rayos-x. Revista Colombiana de Física, Vol. 37, No. 1, 2005. [14] Mössbauer and EPR spectra for glasses and glass-ceramics prepared from simulated compositions of Lunar and Martian soils [15]Instituto Colombiano Agropecuario - ICA, Fertilizantes en diversos cultivos, Centro Experimental Tibaitata, octubre 1981. [16] F. Varret, J. Teillet, Unpublished MOSFIT program (1976). [17] J.G Stevens, A.M. Khasanov, J.W. Miller, H. Pollak, Z. Li. Mössbauer Mineral Handbook. Mössbauer Effect Data Center (2002). 61
  • 66.
    T03 REVISITING THETOLUCA METEORITE R. B. Scorzelli, E. dos Santos 62 and P. Munayco 1Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Rio de Janeiro, 22290-180, Brazil. 2Instituto de Física, Universidade Federal de Mato Grosso, Av. Fernando Corrêa Costa, 2367, Cuiabá, Mato Grosso, Brazil. *Corresponding author: e-mail: scorza@cbpf.br Keywords: Toluca meteorite, Mössbauer, Octahedrites Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology The important TOLUCA shower comprises many thousands of fragments which have been recovered from a rather small area on the hillsides around the village of Xiquipilco, situated in a remote branch of the Toluca Valley network some 25 km north-northeast of Toluca, Mexico. The cumulative weight of all speciemns in registered collections is about 2,100 kg, but it is quite certain that much more material, that can be estimated in ~ 3 tons, has been found and distributed. For centuries the natives of Xiquipilco searched for the iron fragments after each new rainstorm, and they used this iron for the forging of their agricultural implements and iron tools (spades and axes). Toluca first came to be known as a meteorite locality in 1784 which is the year accepted for the first report on the Toluca shower. This 3 ton mass meteorite, is an iron meteorite, classified as a coarse octahedrite, chemical type IAB and when etched, exibit beautiful interwoven Widmansttäten patterns. Iron meteorites, composed of iron-nickel alloys, have played an important role in the study of the iron-nickel phase diagram, due to the fact that they have cooled with a rate of about 1º C/106 years. The Toluca octahedrite, as most of the meteorites belonging to this group, is composed mainly of two Fe-Ni phases, kamacite, bcc structure (- phase) and taenite, fcc structure (-phase). The two phases have definite crystallographic orientations relative to each other forming the so called Widmanstätten pattern (Fig.1). Generally this pattern continues with unchanged orientations throughout the meteorite showing that the meteorite originally, in the high temperature state, was a single crystal with fcc structure. By the very slow cooling process plates of kamacite precipitated along the {111} planes of the fcc crystal, and by growth of the kamacite plates the meteorite finally consists of alternating – and intersecting – plates of kamacite and taenite parallel to the {111} planes of the original fcc crystal. This Widmanstätten pattern is unique for the iron meteorites called octahedrites, basically due to their slow cooling. Figure 1. Widmanstätten pattern Plates of taenite, extracted from bulk material of the Toluca meteorite by selective dissolution of the kamacite in diluted acid, have played an important role in the pioneer study of the Fe50Ni50 ordered phase, tetrataenite. These plates allowed the discovery of tetrataenite using 57Fe Mössbauer spectroscopy (57Fe-MS) [1]. Soon after, also by 57Fe-MS, tetrataenite was detected in the Santa Catharina iron meteorite and in metal particles of chondrites, always associated to a singlet [2]. This phase is the natural analog of synthetic ordered FeNi which has been produced by neutron irradiation of Fe50Ni50 alloys [3]. Rancourt and Scorzelli [4] proposed that the singlet is an antiferromagnetic low-spin -phase (called antitaenite) occurring as an intergrowth with tetrataenite, indicative of an equilibrium state at low temperature in the Fe-Ni system at 25 – 30 at% Ni. Since both phases have the same lattice parameters it is difficult to detect antitaenite with classical XRD. It was only using XRD with synchrotron radiation that the presence of this phase was confirmed for the first time in the Toluca and other iron meteorites, by diffraction methods [5]. References [1] Petersen J. F., Aydin M. and Knudsen J. M. 1977. Phys. Lett. V.62(3)192(1977). [2] Danon J., Scorzelli R. B., Souza Azevedo I. and Michel-Levy M. C. 1979. Nature V.281(1979) 469. [3] Paulevé J., Dautreppe D., Laugier J. and Néel L. 1962. J. Phys. Radium V.23(1962)841. [4] Rancourt D. G. and Scorzelli R. B. J. Magn. Magn. Mater. V.150 (1995) 30. [5] Scorzelli, R. B., Avillez, R. R., Duttine, M. and Munayco, P. Activity Report (LNLS) V.1(2007)1.
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    T03 STRUCTURAL ANDELECTRONIC PROPERTIES OF DISORIENTED SOIL SAMPLES 63 OF CRAFTS CLAY IN TOLIMA, COLOMBIA J.U. González Arias, H. Bustos Rodríguez, F. M. Vargas Fontalvo, D. Oyola Lozano, Y.A. Rojas Martínez, E.A. Ávila Pedraza y G.A. Pérez Alcázar 1Universidad del Tolima. Grupo Ciencia de Materiales y Tecnología en Plasma, A.A.546, Ibagué, Colombia. 2 Universidad del Valle. Grupo Metalurgia Física y Teoría de las Transiciones de Fase, A.A.25360, Cali, Colombia. * mg.ugonzalez@gmail.com Keywords: Mössbauer spectrometry, soils, XRD. Topic: T03- Applications in Soils, Mineralogy, Geology, Cements and Archaeology A study of the mineralogy of clay soils disoriented samples that are used for handicrafts in Guamo-Tolima, using techniques Physicochemical Analyses of soils, X-ray diffraction (XRD) spectrometry Mössbauer (MS), techniques that have been implemented in numerous studies with good results [1-3]. Using Mössbauer spectroscopy (MS) of Fe57 measure parameters such as the deviation hyperfine isomeric (IS), the quadrupole splitting (QS) and the hyperfine field (HF). Particularly the samples of clayey soils at ambient temperature show the presence of mineral phases containing Fe+2 and Fe+3. Also obtained spectra show sextet that identifies the presence of magnetic phases. Also, occurs in other samples doublets characterizing paramagnetic phases. Using refinement programs the respective hyperfine parameters obtained and compared with Mössbauer Mineral Handbook, phases identified as illite, biotite and baumita. Using XRD, identified mineral phases containing iron as baumita (Mg, Mn, Fe, Zn) and also the presence of other phases without iron content as silica (SiO2), montmorillonite [Na0.3 (Al, Mg)2 Si, kaolinite [Al2Si2O5(OH) 4] and Moscow [0.33 (NH4) 2OAl. Clay soils of Chamba Tolima are used to produce one of the best crafts of Colombia globally recognized also by their physical characteristics such as high surface area, cation exchange capacity, absorbency, hydration and swelling, plasticity, thixotropy it has enabled man to give various uses and abundant presence in our environment hence the importance of their study. Our case is an industry that benefits family businesses who applied tradition engaged in this activity from generation to generation, where craftsmanship occurs in fireclay which is recognized nationally and internationally for its beauty and quality. Samples of clay soil of Chamba Tolima, Colombia, were analyzed by different techniques such as physic-chemical analysis, XRD, MS, which allowed us to detect the presence of different mineral phases as calculate hyperfine and structural properties also display phases present containing mainly Fe and Fe+2 y Fe+ 3, (a) (b) Figure 1 Mössbauer spectra adjustment. disoriented samples of clay soils. AC344 sample (a) and shows AC345 (b). The diffractograms were refined using the method Rietvel. The electronic parameters of the phases containing iron (Fe), the isomer shift, splitting quadrupole and hyperfine field were found using Mössbauer spectroscopy and the spectra were refined using a refinement program [4], calculated respective parameters hyperfine and confronted with Mössbauer Mineral Handbook [5]. Figure No. 1 presents the spectra obtained by Mössbauer spectrometry. Coincident with XRD results, are also Fe phases with the presence of Fe+2 and Fe+3. References [1] J. J. Ipus, J. Mojica* y G.A. Pérez Alcázar. Caracterización de arcillas colombianas por espectroscopia Mössbauer y difracción de rayos-x. Revista Colombiana de Física, Vol. 37, No. 1, 2005. [2] Cerón Loayza, María Luisa. Estudio mineralógico de suelos agrícolas por espectroscopia Mössbauer. Tesis de Maestría. UNBA. 2001. [3] STEVENS, J.G., KHASANOV, A.M., MILLER, J.W., POLLAC, H. Y LI, Z.(1998): Mössbauer Mineral Handbook. Mössbauer Effect Data Center, North Carolina 1998. [4] Varret, F. & Teillet, J. (1976). Unpublished MOSFIT program. [5] STEVENS, J.G., KHASANOV, A.M., MILLER, J.W., POLLAC, H. Y LI, Z. (1998): Mössbauer Mineral Handbook. Mössbauer Effect Data Center, North Carolina 1998.
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    T04 ABUNDANCE ANDSTATE OF IRON IN VITAMIN SUPPLEMENTS P.I. Arredondo S., C.A. 64 Barrero, K.E. Garcia and J.M. Greneche 1Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No 52-21, Medellín, Colombia. 2LUNAM, Université du Maine, Institute des Molécules et Matériaux du Mans, IMMM UMR CNRS 6283, Université du Maine 72085 Le Mans Cedex France. *E-mail: patriciaines@gmail.com Keywords: Mössbauer effect, vitamin supplements, sulfate, fumarate, iron state. Topic: T04- Biological and Medical Applications The general forms of iron in vitamin supplements are fumarate or sulfate. It is important for manufacturer as well as for consumer, to know the iron content and its state in these vitamins. The Mössbauer effect is a tool that has been used for that purpose[1]. However, to the best of our knowledge, the relative recoilless f-fractions for these samples have not been yet determined. In this work, the room temperature (RT) relative recoilless f-factors of six purchased commercial vitamins with respect to α-Fe powder were calculated by applying a method of the two relative sub-spectral areas in a mixture of known amounts of the compound and a standard sample [2]. The procedure was repeated three times for different amounts of the compounds and reference. The obtained spectra were thickness-corrected and fitted using commercial software [3]. Figure 1 shows a typical thickness-corrected spectrum of a mixture of Ferro-F-800 and of α-Fe powder, which was fitted with a quadrupolar doublet and a sextet. The spectra for the other samples were similar. The derived hyperfine parameters and the relative f-factors are presented in Table 1. From these parameters, it can be inferred that the states of the irons were Fe2+ in all vitamins, in good agreement with other reports [1]. The relative recoilless f-fractions for the vitamins with respect to α-Fe are also presented. In the case of Laproff vitamin, the amount of iron content was not specified by the manufacturer. However, by using the relative recoilless f-fractions of IRON and Ferro-F-800, which are also vitamins based on iron-sulfates, the amount of iron-sulfate in Laproff was estimated at between 41 and 49 % per tablet; anything else would be excipients. -8 -4 0 4 8 1.00 0.98 0.96 0.94 Relative transmission (a.u.) Velocity (mm/s) Figure 1. RT Mössbauer spectrum of a mixture of Ferro-F-800 and of α-Fe powder. Table 1: RT hyperfine parameters and relative recoilless fractions for some vitamin supplements. Estimated errors are of about 0.01 mm/s for isomer shift , and for quadrupole splitting Δ; and 2% for relative sub-spectral areas. Sample  (mm/s) Δ (mm/s) As /AαFe s/αFe Ferro-F-800 1.25 2.70 19/81 1.10±0.02 Laproff 1.27 2.74 27/73 - IRON 1.28 2.71 12/88 0.91±0.09 Mitrum vitTM 1.16 2.18 3/97 0.66±0.03 Prenavit 1.21 2.25 10/90 1.06±0.06 IOFI 1.21 2.26 23/77 0.86±0.03 References [1] M.I. Oshtrakh, O.B. Milder, V.A. Semionkin. J. Pharm. Biomed. Anal. 40 (2006) 1281–1287. [2] Oh, Sei J., and D. C. Cook. J. Appl. Phys. 85 (1999): 329-332. [3] K. Lagarec and D.G. Rancourt, Recoil: Mössbauer Spectral Analysis Software for Windows, version 1.0 (Department of Physics, University of Ottawa, Canada, 1998).
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    T05 EFFECT OFTITANIA ON THE CHARACTERISTICS OF A TIN‐PLATINUM CATALYST P. Morales-Gil1, N. Nava1 65 and E. Baggio-Saitovitch2 1Instituto Mexicano del Petróleo, Eje Lázaro Cárdenas 152, México D.F. 07730 2) Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, CEP 22290-180, Rio de Janeiro, Brasil *Corresponding author: e-mail: moralesp@imp.mx Keywords: Mossbauer spectroscopy, Pt-Sn Catalyst, dehydrogenation. Topic: T05- Catalysis, Corrosion and Environment Pt-Sn bimetallic catalysts dispersed on alumina are commonly used for reforming and dehydrogenation reactions (1-5). In this research work, Pt and Sn were supported on titania. The resulting interactions between the components in the prepared samples, before and after treatment with hydrogen, were studied by Mossbauer spectroscopy, X-ray diffraction and Rietveld refinement. The results show the presence of Pt and SnO2 after calcinations. After the reduction process, PtSn, and Pt3Sn alloys were identified. The Rietveld refinement analysis shows that some Ti4+ atoms were replaced by Sn4+ atoms in the titania structure. Finally, the Mossbauer spectroscopy and X-ray diffraction results indicate that metallic platinum and SnO2 are encapsulated by a TiOx layer. References [1] L. C. de Menorval, A. Chaqroune, B. Coq and F. Figueras, Journal Chemical Society, Faraday Trans 93 (20) (1997) 3715. [2] L. D. Sharma, M. Kumar, A. K. Saxena, D. S. Rawat, T. S. Prasada Rao, Applied Catalysis A: General 168 (1998) 251. [3] R. D. Cortright, J. M. Hill, J. A. Dumesic, Catalysis Today 55 (2000) 213. [4] T. Inoue, K. Tomishige, Y. Iwasawa, Journal Chemical Society, Faraday Trans 92 (3) (1996) 461. [5] A. Borgna, S. M. Stagg, D. E. Resasco, Journal Physical Chemisty B 102 (1998) 5077.
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    T05 HEMATITE SYNTHESISFROM FERRIHYDRITE TRANSFORMATION: STUDY OF 66 CONVERSION RATE REACTION N. Pariona, K. I. Camacho, J. Quispe-Marcatoma, W. T. Herrera, A. I. Martinez, E. Baggio-Saitovitch 1Centro de investigación y de estudios avanzados del Instituto Politécnico Nacional unidad Saltillo, Coahuila, México. C.P. 25903. 2Facultad de ciencias físicas, Universidad Mayor de San Marcos, Lima, Perú. 3Centro Brasileiro de Pesquisas Físicas, Río de Janeiro, 22290-180, Brazil. *Corresponding author: e-mail: nicolaza.pariona@cinvestav.edu.mx Keywords: Ferrihydrite, Hematite, XRD, Mössbauer Spectroscopy, Magnetization. Topic: T05- Catalysis, Corrosion and Environment. Hematite is widely used as an efficient material for water remediation. The synthesis from ferrihydrite pathway is a practical and economical method. The hematite properties change with many parameters such as: ferrihydrite synthesis, anionic media, pH, reaction time, as well as the kind of catalyst used. The catalysts are used for increasing the reaction velocity and promote the growth of a single crystal phase. Hematite has been synthesized from the transformation of 2-lines ferrihydrite, using NaHCO3 as buffer and adding Fe(II) salts as catalyst in a molar ratio of Fe2+/Fe3+ = 0.02. Mössbauer spectroscopy and magnetometry were used to monitor different stages during the hematite synthesis. We found that hematite is formed since 30 minutes of reaction (figure 1a) and the use of NaHCO3 as buffer is essential to maintain the pH between 7-8 and avoid the formation of other phases like goethite. The XRD study shows that there is no other phase involved in the sample but the Mössbauer analyses (figure 1b) shows that until 150 minutes, residues of 2 lines ferrihydrite are present in the product. References (1) Liu, H.; Ma, M.; Qin, M.; Yang, L.; Wei, Y. J. Solid State Chem. 2010, 183, 2045–2050. (2) Liu, H.; Yang, L.; Ma, M.; Li, P.; Wei, Y. J. Solid State Chem. 2010, 183, 542–546. (3) Cudennec, Y.; Lecerf, A. J. Solid State Chem. 2006, 179, 716–722.
  • 71.
    Figure 1. a)XRD patterns, b) Mössbauer spectrum for the samples at room temperature. 67
  • 72.
    T05 HYBRID HETEROJUNCTIONSBASED ON α‐Fe2O3/CARBON DOTS AS HIGH 68 EFFICIENT PHOTOCALYST UNDER VISIBLE LIGHT Tiago Cabral Araújo1 Henrique dos S. Oliveira,2 José J. Sá Teles,1 Manoel J. M. Pires,1 Luiz C. A. de Oliveira,2 João P. de Mesquita 1, José D. Fabris1* 1Department of Chemistry – Federal University of Jequitinhonha and Mucuri’s valley, MGT 367, CEP 39100-000, Diamantina, MG, Brazil 2Department of Chemistry - Federal University of Minas Gerais, Av. Antônio Carlos, 6627, CEP 31270-901, Pampulha,Belo Horizonte, MG, Brazil. . *Corresponding author: e-mail: jdfabris@ufmg.br Keywords: nanocomposite hybrid, -Fe2O3, carbon dots Topic: T05- Catalysis, Corrosion and Environment Iron oxides are promising candidates for the development of nanophotocatalysts for having good activity and chemical stability under visible radiation. Due mainly to the rapid recombination of the electron–hole pair, Fe2O3 itself usually presents a very lower photocalytical activity [1]. Carbon dots (CDots) are a new class of fluorescent carbon nanomaterials accidentally discovered, during electrophoretic purification of carbon nanotubes [2]. However, for their ability to control radioactive emissions and absorptions, CDots are promising candidates for the development of highly efficient photocatalysts destined to applications in environmental and energy technologies [3]. In this report, it is describe a work devoted to the preparation a hybrid nanophotocatalyst consisting of α-Fe2O3 and carbon nanostructures in aqueous medium, which was used in the photocatalytic degradation of the indigo-carmine dye, in a process activated with visible light (> 400 nm). Figure 1, 57Fe-Mössbauer patterns at 293.5 K: (a) Fe2O3, and (b) Fe2O3/CDots. The heterostructures were obtained with 5 % CDots. Similarly to what can be drawn from the Mössbauer spectra in Figure 1, the powder X-ray diffraction peaks (patterns not shown) are characteristic of -Fe2O3 (JCPDS card # 33-664) indicating that the synthesis of iron oxide with CDots does not significantly change its crystalline structure. The mean coherent length was determined with the Scherrer equation by taking the peak centered at ~33.3 º2, corresponding to the plane (104) The values so obtained were 36.5 and 24.6 nm for the sole -Fe2O3 and the hybrid nanocomposite, respectively. The curves of photocatalytic activity (Figure 2) evidence that the rate of degradation with the -Fe2O3/CDots under visible light (> 400 nm) is much higher, between the two materials. Figure 2. Photocatalytic activity of the materials prepared as measured through the degradation of the indigo-carmine dye.
  • 73.
    Preliminary results suggestthat the catalytic activity is promoted by CDots anchored on the surface of the oxide particles. This arrangement tends to increase the concentration of substrate molecules on the surface of the photocatalyst, thus the light-absorbing capacity, and lower rate of recombination of electron-hole pair. References [1] Li, H.; Kang, Z.; Liu, Y.; Lee, S.-T. Journal of Materials Chemistry 2012, 22, 24230. [2] Xu, X.; Ray, R.; Gu, Y.; Ploehn, H. J.; Gearheart, L.; Raker, K.; Scrivens, W. A. Journal of the American Chemical Society 2004, 126, 12736. [3] Sivula, K.; Zboril, R.; Le Formal, F.; Robert, R.; Weidenkaff, A.; Tucek, J.; Frydrych, J.; Grätzel, M. Journal of the American Chemical Society 2010, 132, 7436. 69
  • 74.
    T05 IRON NANOSTRUCTURESSYNTHESIZED BY PULSED PLASMA IN LIQUIDS FOR 70 THE REMOVAL OF CHROMIUM IN WATER O. Olea-Mejía, A. Cabral- Prieto, U. Salcedo-Castillo, O. Olea-Cardoso and R. López-Castañares 1 Centro Conjunto de Investigación en Química Sustentable CCIQS UAEM-UNAM. Facultad de Química. Universidad Autónoma del Estado de México.Toluca, Estado de México. 2 Instituto Nacional de Investigaciones Nucleares, Departamento de Física, Apdo. Postal 18-1027, México. D. F., México. 3 Facultad de Química. Universidad Autónoma del Estado de México.Toluca, Estado de México. *Corresponding author: e-mail: oleaoscar@yahoo.com.mx Keywords: Pulsed Plasma in Liquids, Water Treatment Topic: T05- Catalysis, Corrosion and Environment Iron and iron compounds in the nanometric scale have been widely used for removal of pollutants in water. Chemical methods for the synthesis of nanoparticles yield in many cases undesired by-products and/or particles covered with different molecules. This is a problem when treating water since the nanoparticles surface is not in close contact with the pollutant to be removed. To avoid this problem several physical methods exist to create nanostructures. In this work we used the Discharge Plasma in Liquid to form iron and/or iron oxides nanostructures; this technique yield uncovered particles in solution and no chemical by products are produced other than ionic Fe species. We used a DC Power source and a commercial Soldering Iron to produce de Pulsed Plasma. Particles were characterized by TEM to study their sizes and shapes. In order to investigate about the chemical species of iron, Mossbauer Spectroscopy was performed on the different samples (Figure 1). Once the colloid is formed, orange skin is impregnated with these nanoparticles for the removal of Cr+6. The water treatment experiments were conducted in a batch system at different concentrations of nanostructures and with pure orange skin at a concentration of Cr+6 of 50 ppm. The skin can alone remove some Cr+6 from the polluted water. However, when using iron based nanostructures supported on the orange skin, the removal is much higher and the final concentration in the mother solution can reach a few ppm or even zero ppm (Table 1). Figure 1 Mossbauer spectrum (experimental and deconvolusions) of Fe produced in methanol. Table 1 Chromium removal by the orange skin – Fe composites at different experimental conditions. Refernces [1] Wilkin, R. T., Su, C., Ford, R. G., & Paul, C. J. (2005). Chromium-removal processes during groundwater remediation by a zerovalent iron permeable reactive barrier. Environmental science & technology, 39(12), 4599-4605. [2] López-Téllez, G., Barrera-Díaz, C. E., Balderas-Hernández, P., Roa-Morales, G., & Bilyeu, B. (2011). Removal of hexavalent chromium in aquatic solutions by iron nanoparticles embedded in orange peel pith. Chemical Engineering Journal, 173(2), 480-485.
  • 75.
    T05 MAGNETIC HETEROGENEOUSCATALYST FOR THE CONVERSION OF TRIACYLGLEROLS IN THE OIL OF MACAÚBA (Acrocomia aculeata) FRUITS INTO METHYL ESTERS 71 A. L. Macedo, J. D. Fabris, M. C. Pereira, M. J. M. Pires, W. L. Oliveira, J. D. Ardisson 1DSc student in Biofuels at Federal University of the Jequitinhonha and Mucuri Valleys dos Vales Jequitinhonha e Mucuri (UFVJM), 39100-000 Diamantina, MG, Brazil 2PRPPG - UFVJM, Campus JK, 39100-000 Diamantina, MG, Brazil 3Institute of Science, Engineering and Technology, UFVJM, 39803-371 Teófilo Otoni, MG, Brazil 4Institute of Science and Technology, UFVJM, 39100-000 Diamantina, MG, Brazil 5Center for the Development of Nuclear Technology (CDTN/CNEN), 31170-130 Belo Horizonte, MG, Brazil *Corresponding author: jdfabris@gmail.com Keywords: Biofuels, iron oxide, biodiesel, transesterification, macaúba T05- Catalysis, Corrosion and Environment The intensive search for optimized chemical industrial processes to produce biofuels has been bringing about, in more recent times, scientific efforts towards the research and development of new efficient heterogeneous catalysts specifically directed to convert triacylglicerols and free fatty acids of bio-oils into their corresponding mixture of methyl (also, ethyl) esters. The resulting mixture of esters essentially forms the so known biodiesel and biokerosene fractions, which may be and, often are, blended, respectively, with the mineral diesel or kerosene, to form the alternative fuel to power internal combustion engines or airplane turbines. This report describes a work being devoted to the synthesis of nanosized magnetic iron oxide and its composite catalyst formed with KI-functionalized silica to form the heterogeneous catalyst to be used on the transesterification of triacylglicerols in the oil from the seed core of fruits of the macaúba palm (Acrocomia aculeata) into methyl esters. The magnetic iron oxide was obtained by mixing FeCl3 and FeCl2 in molar ratio of 2:1 in an aqueous alkaline medium, followed by centrifuging and lyophilizing the product after a 30 min-reaction. The individual solid components and the composite itself were first characterized for their chemical, crystallographic and 57Fe hyperfine structures by X-ray fluorescence, powder X-ray diffractometry (XRD) and Mössbauer spectroscopy. The room temperature (˜298 K) Mössbauer spectrum of the sole magnetic iron oxide nanopowder is shown in Figure 1(a). This spectrum is formed by broad resonance sextets due to the coupling of the magnetic hyperfine field with the dipolar magnetic moment at 57Fe nuclei on both Fe3+ in tetrahedral and, probably, mixed valence Fe3+/2+ in octahedral coordination of the iron oxide spinel structure, as it could be deduced from XRD data (pattern not shown). Fitting the Mössbauer spectrum with an independent model of hyperfine fields distribution may lead to confirm the putative occurrence of, even though eventually not only, superparamagnetic magnetite (Fe3O4) in some relatively broad distribution of sizes of very small particles. a) b) Figure 1. Mössbauer spectra (a) at room temperature (˜298 K) for the synthesized magnetic iron oxide and (b) at 150 K for the sample of KI-functionalized silica composite with magnetic iron oxide after being used as catalyst on the transesterification reaction. Further Mössbauer measurements, at room (˜298 K) and lower (298 K > T > 120 K) temperatures, for the magnetic composite catalyst material, before and after being used in the transesterification reaction, are currently in progress. The Mössbauer spectrum for the sample at 150 K (Figure 1(b)) after being used as catalyst indicates the occurrence mainly of maghemite (γ-Fe2O3) as magnetic iron oxide. The chemical effectiveness of this catalyst on the transesterification reaction with methyl alcohol, as evaluated by analyzing the produced methyl-esters mixture with gas chromatography coupled with mass spectrometer, was found to be indeed very promising to the production of biofuels.
  • 76.
    Acknowledgements: Work supportedby FAPEMIG and CNPq (Brazil). ALM thanks CAPES (Brazil) for sponsoring her DS studentship at UFVJM. JDF is also indebted to CAPES for granting his Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. 72
  • 77.
    T05 MILLING OF2‐FERRIHYDRITE AND AKAGANEITE AND ITS EFFECT ON THEIR Difractogramas superpuestos 2-Ferrihidrita 2-Ferr. Molida I 40 50 60 70 80 2 theta 73 ADSORPTION OF ARSENIC (v) K. E. García, C. Aristizabal and C. A. Barrero Grupo de Estado Sólido, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Calle 70 # 52-21, Medellín, Colombia. *Corresponding author: e-mail: kgarciat05@gmail.com Keywords: Adsorption of arsenic, iron oxides, milling Topic: T05 - Catalysis, Corrosion and Environment Adsorption of arsenic (As) has been studied using a variety of adsorbents, including: phyllosilicates, silica, iron oxides and aluminum oxides. The modification of the surface of these particles plays an important role in their adsorption capabilities. The use of iron oxides has a great advantage due to their large surface areas, which allows the presence of abundant active sites for adsorption. Arsenic (V) is a toxic element which can cause serious health problems to the population exposed to it [1]. The routes of human exposure are basically air, water or food. In a previous work, pure and Al-doped akaganeites were prepared in the presence or absence of urea [2]. It was found that the maximum adsorption of As was for Al-doped -FeOOH prepared in 0.4 M urea, which was named as -Fe(Al)OOH-urea. In this work, we compare the As adsorption capabilities of un-milled and ball milled -Fe(Al)OOH-urea and 2-line ferrihydrite. The milling is performed with the purpose to modify the nanostructure of the oxides. This process was done in air at atmospheric pressure and at room temperature in a Fritsch Pulverisette 5 planetary ball mill, using agate vials of 250 ml in volume and balls of 10 mm in diameter made of the same material. The angular speed of disc was of 100 rpm, the ball to powder mass ratio was of 1:20, and the milling time was of 3 h. The room temperature Mössbauer spectra (RT-MS) of milled and un-milled -Fe(Al)OOH-urea samples were fitted with two doublets showing similar hyperfine parameters [3]. On the other hand, the RT-MS for the milled and un-milled ferrihydrites were fitted by introducing a single doublet with similar hyperfine parameters [3]. XRD (see Figure 1), FTIR and RAMAN spectroscopy also demonstrated that akaganeite and 2- line ferrihydrite are the only compounds presented in the un-milled and milled samples, and that therefore the milling did not induced transformation to other phases. The kinetics of As absorption was determined by atomic adsorption spectroscopy, and was performed by adding 0.1g of the adsorbent into a 200 ml solution containing 600 ppb of As (V) at pH 7.0 and at RT. We have found that the milling did not improve the adsorption capability of the 2-line ferrihydrite. However, the As (V) adsorption of un-milled akaganeite after 60 min of initiated the kinetic process was higher in comparison to the As adsorption of the milled sample. The As adsorption capability at 60 min followed the order: milled-ferrihydrite  un-milled-ferrihydrite  un-milled--Fe(Al)OOH-urea  milled--Fe(Al)OOH-urea. Because, the adsorption process involves the interaction of adsorbing species with surface hydroxyl and other groups of the iron oxides, it is probable that these active surface sites are modified by the milling, particularly in the case of the akaganeites. 1,0 0,8 0,6 0,4 0,2 0,0 I nt ens i dad R el at i v a Figure 1. XRD patterns of milled (green lines) and un-milled 2-Ferrihydrites (blue lines). nt ensi t y References [1] K. A. Matis, M. Lehmann, A. I. Zouboulis, P. Misaelides et al. eds, Natural Microporus Materials in Environmental Technology, Kluwer Academic Publishers, The Netherlands, 1999. pp. 463-472. [2] K. E. García, A. E. Tufo, E. E. Sileo and C. A. Barrero, Book of Abstracts of XII Latin American Conference on the Applications of the Mössbauer Effect, LACAME-2010, Lima, Peru, Nov. 2010. ISBN 978-612-4072-08-6, Abstract T05117, p. 158. [3] R.M. Cornell and U. Schwertmann. 2003. The Iron Oxides: Structure, Properties, Reactions, Ocurrences and Uses Preparation and Characterization, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
  • 78.
    T05 SORPTION OFCHROMIUM (VI) BY Mg/Fe HYDROTALCITE TYPE COMPUNDS I. García-Sosa, A. Cabral- 74 Prieto N. Nava), M.T. Olguín, Luis Escobar, R. López- Castañares, O. Olea- Cardoso (1). Departamento de Química, Instituto Nacional de Investigaciones Nucleares, Apartado postal No. 18-1027, Col. Escandón, Del. Miguel Hidalgo, 11801, México D. F., México;, irma.garcia@inin.gob.mx, e-mail:agustin.cabral@inin.gob.mx teresa.olguin@inin.gob.mx;(2). Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas, 152, Col. San Bartolo Atepehuacan, Del. Gustavo A. Madero, C. P. 07730, México D. F.; email: tnava@imp.mx; (3). Facultad de Química, Universidad Autónoma del Edo. de México, Toluca Edo. de México, México; email: rlc@anuies.mx, olc@anuies.mx *Corresponding author: e-mail: agustin.cabral@inin.gob.mx Keywords: Hydrotalcites, Cr(VI), environment Topic: T05- Catalysis, corrosion and environment Layered double hydroxides (LDHs), also known as hydrotalcites or anionic clays, have the general formula [M2+(1-x) M3+x (OH)2]x+[Am-x/m●nH2O], where M2+ could be Mg(II) and M3+ could be Al (III) or Fe(III), and Am- is an exchangeable anion. These compounds are mainly utilized as catalysis precursors, but they have also been used for removal of contaminants such as chromium [1, 2], among other processes. In recent years, several authors have documented the use of LDHs [1] for chromium removal from wastewater, observing that these methods are environmentally friendly. So far, a few reports have been published on the adsorptive behavior of Mg/Fe LDHs for the removal of chromium [2]. These types of compounds are mainly synthesized by co-precipitation [2]. In this work the synthesis products of Mg/Fe LDH compounds poorly, HTFeMO9A, and well crystallized, HTFeMO9A, samples were studied. Batch system was used to determine the sorption isotherms with 100 mg of any of these samples which were put in contact with 10 mL of different concentrations of potassium dichromate (K2Cr2O7) (from 5 to 100 mg K2Cr2O7/L at pH values of 3 and 5. The adsorbed average quantity of K2Cr2O7 per gram of LDH was around 6.3 mg/g. This value is twice higher than the one reported by Das [2] for Mg/Fe LDH compound without any calcination. Ferrihydrite in both LDH samples was always detected from Mössbauer and Raman spectroscopies, Figs. 1 and 2, respectively. A discussion of its presence in the sorption of K2Cr2O7 is made. Raman spectra are characteristic of LDHs having a ratio of Fe3+/(Mg2+ + Fe3+)  0.5, the presence of ferrihydrite makes, however, ambiguous this conclusion. On the other hand, the presence of the chromate anions after the sorption process are easily detected from these Raman spectra, an aspect that is important for this study. Conclusions. The prepared Mg2+/Fe3+ LDHs result to be viable for the adsorption of contaminants. The role of ferrihydrite in this sorption process must be further studied to understand the sorptive properties of these compounds
  • 79.
    Figure 1 showsthe Mössbauer spectrum of HTFeMo9A recorded at room temperature and analyzed with triangular distributions. Figure 2 Raman spectra of hydrotalcite before and after Cr(VI) sorption. References [1] Kok-Hui Goh, Teik-Thye Lim, Zhili Dong. Application of layered double hydroxides for removal of oxyanions: A review Water Research 42, (2008) 1343-1368 [2] J. Das, D. Das, G. Prasad Dash, D. Prakasini Das and . Parida “Studies on Mg/Fe hydrotalcite –like compound (HTlc): Removal of chromium (VI) from aqueous solution” Intern. J. Environ. Studies 61 (5) (2004) 605-616 75
  • 80.
    T05 THE ACIDITYAFFECTING THE SURFACE CHARGE OF FERRIHYDRITE/ZEOLITE COMPOSITE AND THE ABILITY TO REMOVE ARSENATE FROM AQUEOUS MEDIUM 76 C.Pizarro1,2, L. Gaete1,2, M.F. Albornoz1,2 , P. Sanchez1, J.D. Fabris3,4, M. Escudey1,2 and J.D. Ardisson5 1 Facultad de Química y Biología. Universidad de Santiago de Chile. Santiago, 725475. Chile. 2 Centro para el Desarrollo de la Nanociencia y Nanotecnología (CEDENNA). Santiago, 725475, Chile. 3 Departamento de Química - ICEx, UFMG. Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil. 4 Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM). Campus JK, 39100-00 Diamantina, MG, Brazil. 5 Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN), Campus – Pampulha, 31170-130 Belo Horizonte, MG, Brazil *Corresponding author: e-mail: carmen.pizarro@usach.cl Keywords: pH effects, arsenic, composite ferrihydrite Topic: T05- Catalysis, Corrosion and Environment The effectiveness of adsorbent materials to remove arsenate polluting natural water bodies depends on the surface charge, crystalline structure and surface area of the adsorbing material. Ferrihydrite is a poorly crystalline iron oxide with high surface area and variable surface charge. It is reported the work relating the effect of the acidity of the aqueous medium affecting the surface charge and consequently the adsorption ability of ferrihydrite/zeolite composite to remove arsenate from aqueous medium. The composite was prepared with a natural zeolite coated with 23 mass% of ferrihydrite synthesized according to the procedure described by Schwertmann and Cornell [1]. The ferrihydrite and the composite samples were characterized for their specific surface area (SSA), hyperfine structure assessed with 57Fe Mössbauer spectroscopy, crystallographic features with powder X-ray diffraction (XRD) and also for some of their morphological aspects, with optical analysis. The 298 K - Mössbauer spectra (Figure 1 and Table 1) for these samples show an intense doublet of the characteristic paramagnetic Fe3+ in ferrihydrite [2]. The found SSA values for this ferrihydrite and for its composite were 261 ± 3 m2g-1 and 107 ± 3 m2g-1, respectively. The arsenate adsorption kinetics at both pH 7.5 and 4.5 follows a pseudo-first order model; the maximum adsorption is achieved after 120 min. Fitting data to the Langmuir model leads to a maximum of arsenate adsorption of 36.6 and 46.08 mg g-1 at pH=7.5, for the sole ferrihydrite and the composite, respectively. If the pH of the aqueous medium is adjusted to pH=4.5, rather away from the point of zero charge of ferrihydrite (pH = 8.0), the arsenate adsorption capacity of these materials increases significantly up to 56.28 and 86.03 g g-1, for the sole ferrihydrite and the composite samples, respectively. From these results, controlling the pH value is a critical condition to assure the suitable effectiveness of the adsorbing capacity of these materials with variable charge surface to optimize the arsenate removal from aqueous systems. Figure 1. 298 K-Mössbauer spectra for the ferrihydrite (Fh) and its composite (FhZ-23) Table 1. 57Fe hyperfine parameters for the ferrihydrite (Fh) and for the ferrihydrite/zeolite composite (FhZ-23) at 298K. δ(Fe) = isomer shift relative to Fe; 2ε = quadrupole shift and RA = relative subspectral area. Sample δ(Fe)/mm s-1 2ε/mm s-1 RA/% FhZ-23 0.34 0.67 100 Fh 0.33 0.65 100 References [1] Schwertmann U., Cornell R.M. (2003). Iron Oxides in the Laboratory. Preparation and Characterization.Editorial Wiley-VCH, second edition, pp 11. [2] Murad, E. (2010). Mössbauer spectroscopy of clays, soils and their mineral constituents. Clay minerals, Volume 45, Number 4, pp. 413–430. Acknowledgments: Work supported by DICYT-USACH 021242PA, CEDENNA FB-0807 (Chile), CNPq (grants # 487148/2013-4; 124629/2013-0 and 305755-2013-7) and FAPEMIG (Brazil). JDF is also indebted to CAPES (Brazil) for granting his visiting professorship at UFVJM under the PVNS program.
  • 81.
    T06 MÖSSBAUER SPECTROSCOPICSTUDY OF CALCIUM SUBSTITUTION IN THE Sm1‐ xCaxFeO3‐δ (0.1 ≤ x ≤ 0.5) SYSTEM PREPARED BY SOL‐GEL BASED PECHINI METHOD 77 A. M. Huízar-Félixa, E. Legarrab, D. Meridab, F. Plazaolab, T. Hernández a Laboratorio de Materiales I, Centro de Laboratorios Especializados, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, Av. Pedro de Alba S/N, C.P. 66450, San Nicolás de los Garza, Nuevo León, México b Elektrizitate eta Elektronika Saila, Euskal Herriko Unibertsitatea UPV/EHU, p.k. 644, 48080 Bilbao, España . *Corresponding author: e-mail: tomas.hernandezgr@uanl.edu.mx Keywords: sol-gel processes; crystal structure; oxide materials; Mössbauer spectroscopy; vacancy formation; hyperfine interactions Topic: T06- Chemical Applications, Structure and Bonding Perovskite series Sm1-xCaxFeO3-δ (0.1 ≤ x ≤0.5) were obtained by sol-gel Pechini method. XRD analysis and Mössbauer spectroscopy were employed to characterize the synthesized perovskites. The system was found to be a pure phase with minimum distortion of the crystalline structure. The Mössbauer measurements (Figure 1) revealed the presence of Fe3+, Fe4+ and Fe5+ charge states. The presence of Fe5+ in all the samples confirms the occurrence of charge disproportionation (2Fe4+ → Fe3+ + Fe5+) at 293 K. The introduction of non-magnetic Ca atoms on Sm positions produces the appearance of several octahedral Fe3+ positions. For the samples with the lowest Ca content (x = 0.1, 0.2 and 0.3) the areas of the octahedral Fe3+ positions obey the binomial distribution indicating that the Ca atoms place randomly in Sm positions and the amount of Fe4+ is sufficient in order to avoid the formation of vacancies. In contrast, above 30% Ca the amount of Fe4+ cannot be increased, and for x=0.4 and x=0.5 the samples present oxygen vacancies, which results in tetrahedral Fe3+ positions. Figure 1. Mössbauer spectra of Sm1-xCaxFeO3-δ system (0.1 ≤ x ≤ 0.5). Grey sextets correspond to Fe3+ in octahedral positions, orange sextet corresponds to Fe3+ in tetrahedral position, blue and red sextets correspond to Fe3+ and Fe5+ due to charge disproportionation, green sextet corresponds to Fe4+ and brown singlets correspond to paramagnetic Fe3.5+.
  • 82.
    T08 57Fe AND119Sn MÖSSBAUER STUDY OF Fe DOPED SnO2 OBTAINED BY 78 MECHANICAL MILLING L.C. Sánchez1*, J. J. Beltrán2, J.A. Osorio2, E. M. Baggio- Saitovitch3 and C. A. Barrero2 1Grupo Avanzado de Materiales y Sistemas Complejos-GAMASCO, Universidad de Córdoba, Colombia. 2Grupo de Estado Sólido, Sede de Investigación Universitaria, Universidad de Antioquia, Colombia 3Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca. CEP 22290-180, Rio de Janeiro, Brasil. *Corresponding author: e-mail: luiscarlos@correo.unicordoba.edu.co Keywords: Fe doped SnO2, Mechanical milling, Mössbauer spectroscopy. Topic: T08- Magnetism and Magnetic Materials Powders of SnO2 doped with iron were prepared from mechanical alloying in a planetary ball mill Fritsch Pulverisette 5 and using like precursors: SnO2 and metallic iron (α-Fe). Were investigated as the structural and magnetic properties of products are affected, due to the influence of different conditions of milling such as: powder to ball weight ratio (1:20, and 1:40); time of milling (6, 12, 18 and 24 hours); speed of rotation of the support disc (250 and 390 rpm) and concentration of the dopant (1, 4 and 8 at%). All the millings were conducted to room temperature and atmospheric pressure. Additionally, a structural and Mössbauer analysis was made of the evolution of the pure and Fe doped SnO2 submitted to milling. The 119Sn Mössbauer spectra of the samples consist of two doublets. The parameters of the doublets are only assigned to the presence of Sn4+. The first doublet correspond well to those characteristics of bulk SnO2, while the second doublet can be associated with a much distorted Sn microenvironment due to a neighboring crystal defect like a vacancy (see Fig. 1). Figure 1. Room temperature 119Sn Mössbauer spectra of Fe (8% at.) doped SnO2, obtained by milling during 12 and 18 h. The 57Fe Mössbauer spectra of the samples consist of one or two doublets, and one sextet. The parameters of the first doublet are assigned to the presence of Fe3+ in octahedral sites, which suggest substitution of the Fe by the Sn in the structure of the SnO2 (Fig. 2). Additionally a second doublet was observed, whose parameters suggest the presence of Fe2+. Rodriguez Torres and coauthors [1] suggest the presence of states of oxidation Fe2+ and Fe3+ for the milled samples of SnO2 with α-Fe, which would correspond to iron ions with different environments. Of another part, the parameters of the sextet detect the presence of α-Fe, corresponding to the part of the powder that was not incorporated to the structure of the SnO2. By using density functional theory calculations, we explore the effects of Fe on the structural, electronic and magnetic properties of the samples. Figure 2. Room temperature 57Fe Mössbauer spectra of Fe (4 and 8% at) doped SnO2, obtained by milling during 12 h. References [1] C. E. Rodríguez Torres, A. F. Cabrera and F. H. Sánchez. Physica B 389 (2007) 176
  • 83.
    T08 A MAGNETOMETRYAND MÖSSBAUER SPECTROSCOPY STUDY OF THE TRANSFORMATION OF FERRIHYDRITE WITH COBALT AS CATALYST 79 K. I. Camacho*1, J. Quispe- Marcatoma2,3, W. T. Herrera2,3, A. I. Martinez1, E. Baggio-Saitovitch3 1Centro de investigación y de estudios avanzados del Instituto Politécnico Nacional unidad Saltillo, Coahuila, México. C.P. 25000. 2Facultad de ciencias físicas, Universidad Mayor de San Marcos, Lima, Perú. 3Centro Brasileiro de Pesquisas Físicas, Río de Janeiro, 22290-180, Brazil. *Corresponding author: e-mail: kicamachoa@cinvestav.mx Keywords: Ferrihydrite, Hematite, Magnetite, Cobalt, NaHCO3, XRD, Mössbauer Spectroscopy, Magnetization. Topic: T08- Magnetism and Magnetic Materials. Iron oxides have been used for degradation of organic compounds in water with a reaction similar to the effected by peroxidase. Hematite and cobalt ferrite nanoparticles have shown a great capability for prussian blue degradation. Hematite and magnetite nanoparticles have been synthetized from the transformation of 2-line ferrihydrite (2LF), using cobalt dications as catalyst and NaHCO3 as pH-buffer. Cobalt ions with different percents of cobalt (RCo0%, RCo0.05%, RCo1%, RCo3%, RCo5%. RCo15% and RCo20%) were added, and the ferrihydrite transformation was followed by Mössbauer spectroscopy and magnetometry (figure 1). It was found that cobalt ions induce the formation of magnetite at higher percent and hematite is formed at lower percent. Additionally, the formation of other phases such as goethite and lepidocrocite was avoided during the transformations. On the other hand, magnetic measurements indicated that hematite growths with very low coercive fields that do not depends on the cobalt concentration. However, magnetite samples, where no clear difference between their XRD patterns is observed (see figure 1a for RCo15% and RCo20%), the magnetization measurements shown that cobalt strongly affects the coercive field in the samples. Mössbauer spectroscopy fittings confirm the formation of hematite and magnetite in each case, but small amounts of 2-line ferrihydrite were detected yet (figure 1b). References (1) Liu, H.; Ma, M.; Qin, M.; Yang, L.; Wei, Y. J. Solid State Chem. 2010, 183, 2045–2050. (2) Cornell, R. M.; Giovanoli, R. Polyhedron 1988, 7, 385–391. (3) Cornell, R. M.; Giovanoli, R. Clay Clay Miner. 1989, 37, 65–70.
  • 84.
    Figure 1. a)XRD patterns, b) Mössbauer spectrum for the samples at room temperature. 80
  • 85.
    T08 DETERMINATION OFTHE RELATIVE RECOILLESS F‐FACTOR FOR THE ORTHOFERRITE NdFeO3 SYNTHETIZED BY SELF‐COMBUSTION METHOD 81 L.A Morales1, O. Arnache2, C. Barrero2, and G.A. Sierra1 1 Departamento de Materiales y Minerales, Facultad de Minas, Universidad Nacional de Colombia, Calle 75 # 79A-51, Bloque M17, Medellín, Colombia 2 Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia - UdeA, Calle 70 No. 52-21, A.A. 1226, Medellín, Colombia. *Corresponding author: e-mail: cbarrero@fisica.udea.edu.co Keywords: Orthoferrite, Relative F-factor, self- combustion. Topic: T08 - Magnetism and Magnetic Materials The NdFeO3 compound was synthesized by the self-combustion method. The Rietveld refinement of the XRD pattern proved the purity of the phase and it was fitted using the space group Pbnm, Perovskite type (see Fig.1). Using the Scherrer equation, the average crystal size was estimated to be 75.3 nm. The ZFC and FC curves showed an antiferromagnetic behavior, which was also evident in the M vs H curves at 300 K. Figure 1. Diffractogram and ICSD pattern of the NdFeO3 compound After the structural and magnetic analysis, this work also reports the room-temperature relative recoilless F-factor of the NdFeO3 compound. This was made by applying a method based on the correct determination of the two subspectral areas present in a mixture of known amounts of the compound under study and a standard sample [1], which in our case was iron powder. The procedure was repeated three times for different amounts of the compounds. The obtained spectra were thickness-corrected and fitted using the commercial software Recoil [2] (see Fig. 2). The relative recoilless F-fraction for the NdFeO3 with respect to α-Fe was calculated to be 1,15േ0.03, a result which compares reasonably well with that value predicted by the Debye model and the reported Debye temperatures for these two compounds.
  • 86.
    Figure 2. FittedMössbauer spectra for the three amounts of the mixture NdFeO3 - αFe References [1] Oh, Sei J., and D. C. Cook. Journal of applied physics 85.1 (1999): 329-332. [2] K. Lagarec and D. G. Rancourt, Recoil: Mössbauer Spectral Analysis Software for Windows, version 1.0 (Department of Physics, University of Ottawa, Canada, 1998). 82
  • 87.
    T08 EFFECT OFCo2+ IN STRUCTURAL AND MAGNETIC PROPERTIES OF COBALT FERRITES OBTAINED BY THE COPRECIPITATION METHOD 83 A. A.Velásquez1,*, S. Venegas1 and J.P.Urquijo2 1Grupo de Electromagnetismo Aplicado, Universidad EAFIT, A.A. 3300, Medellín, Colombia 2Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia, A.A. 1226, Medellín, Colombia *Corresponding author: avelas26@eafit.edu.co Keywords: Cobalt ferrites, Mössbauer spectroscopy, coprecipitation method Topic: T08- Magnetism and Magnetic Materials In this paper we study the effect of divalent cobalt on the structural and magnetic properties of cobalt ferrites, Fe3-xCoxO4, substituted at weight percentages of 5%, 10%, 15%, 20% and 30%, which were synthesized by the coprecipitation method. Several effects were observed as the Co2+ concentration increases in the starting solutions: X-ray diffraction measurements showed a sequential increasing of the lattice parameter, while room temperature Mössbauer measurements showed a progressive reduction of the spectral area of the Fe2.5+ sub spectrum relative to the area of the Fe3+ sub spectrum, as well as a reduction in the hyperfine magnetic field of the Fe2.5+ sub spectrum ions while the hyperfine magnetic field of the Fe3+ sub spectrum remained almost constant. The results suggest a progressive incorporation of ions Co2+ in the octahedral sites of ferrite, where they substitute Fe3+ ions, expanding the crystalline structure and promoting vacancy generation. Figure 1. Room temperature Mössbauer spectrum of the 5 wt.% Co2+ cobalt ferrite. References [1] Sorescu.Monica, Diamandescu.L., Tarabasanu-Mihaila.D., Materials Letters 59 (2005) 22-25 [2] Sorescu.Monica, Journal of Nanoparticle Research 4 (2005) 221 [3] Velásquez.A.A., Morales.A.L., Urquijo.J.P., Baggio.E., Hyperfine Interactions 203 (2011) 75-84ö
  • 88.
    T08 Fe‐DOPED SnO2NANOPOWDERS OBTAINED BY MECHANOCHEMICAL 84 ALLOYING AND THERMAL TREATMENT OF SnCl2 L.C. Sánchez1*, J. J. Beltrán2, J.A. Osorio2, E. M. Baggio- Saitovitch3 and C. A. Barrero2 1Grupo Avanzado de Materiales y Sistemas Complejos-GAMASCO, Universidad de Córdoba, Colombia. 2Grupo de Estado Sólido, Sede de Investigación Universitaria, Universidad de Antioquia, Colombia 3Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca. CEP 22290-180, Rio de Janeiro, Brasil. *Corresponding author: e-mail: luiscarlos@correo.unicordoba.edu.co Keywords: Tin oxide nanoparticles; Fe doping; Mechanochemical milling and thermal treatment. Topic: T08- Magnetism and Magnetic Materials In this work, Sn1-xFexO2 (x=0, 0.03, 0.05, 0.08 and 0.10) nanoparticles were synthesized by mechanochemical alloying of anhydrous SnCl2 (or SnCl2•2H2O), FeCl3 and Na2CO3, with NaCl added as diluents. The as-milled mixtures were subsequently heat treated at 600 °C during 3 hours, in air atmosphere, and finally washed with double deionized water. NaCl is used in order to improve the milling characteristics of the reactant powders. The mechanochemical processes was performed in a planetary ball mill Fritsch Pulverisette 5, using Cr-based stainless steel jars and balls of 12 mm in diameter. The rotation velocity of the disc was of 250 rpm, and the ball to powder ratio was of 20:1. Samples were milled for 3 and 12 hours in atmospheric conditions. The overall reaction is accounted for by: SnCl2 + Na2CO3 → SnO +2NaCl +CO2, and the heat treatment of the milled-product in oxygen is followed in order to oxidize SnO to SnO2 [1]. X-ray diffraction patterns of all Sn1-xFexO2 samples showed peaks due to the cassiterite phase of SnO2. The Raman spectra exhibit bands of SnO2, and the presence of hematite for some samples. Changes in the intensity, FWHM, area, and position of the vibrational bands with Fe doping concentration were observed. 57Fe Mössbauer spectra of Sn1-xFexO2 samples were composed of magnetic and paramagnetic signals (see Fig. 1). The paramagnetic signals pointed to an incorporation of the Fe3+ ions into the SnO2 crystallographic structure. It was found that by using anhydrous-SnCl2 and SnCl2•2H2O, the final product was a mixture of hematite plus Sn1-xFexO2, but hematite was less abundant for the former sample. 119Sn Mössbauer spectra for all samples indicated only the presence of Sn4+ in octahedral sites. Room temperature hysteresis loops for an impurity-free sample consisted of contributions coming from paramagnetic and ferromagnetic signals, which could be related to an inhomogeneous distribution of the iron ions in the crystallographic structure (see Fig. 2). Our results suggested that 3 hours of milling, instead of 12 hours, low iron concentrations and the use of anhydrous SnCl2, instead of SnCl2•2H2O, can give better conditions to produce impurity free samples. a) Figure 1: RT 57Fe Mössbauer spectra of Sn1-xFexO2 (x=0.03, 0.05, 0.08 and 0.10) samples obtained from SnCl2 for 12 h of milling time. b) Figure 2: RT hysteresis loop of Sn1-xFexO2 (x=0.03) sample obtained for 12 h of milling time. The experimental data, the fitted curve and the paramagnetic and ferromagnetic contributions are shown. References [1] H.M. Yang, Y.H. Hu, A.D. Tang, S.M. Jin, G.Z. Qiu, J. Alloys Comp. 363 (2004) 271.
  • 89.
    T08 INTERACTION OFGOLD CLUSTERS WITH MAGNETITE NANOPARTICLES AND ITS 85 EFFECTS ON THE MAGNETIC PROPERTIES L. León Félix1, J. Mantilla, J. A. H. Coaquira1, M. A. R. Martinez1, M. Parise1, L. De Los Santos Valladares2, A. Bustamante3, V. K. Garg1, A. C. Oliveira1 and P.C. Morais 1Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília, DF 70910-900, Brazil. 2Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom. 3Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima, Perú. *Corresponding author: e-mail: lizbetlf@gmail.com Keywords: Au-coated magnetite nanoparticles, HRTEM, Mössbauer spectroscopy. Topic: T08- Magnetism and Magnetic Materials. The synthesis of core/shell iron oxide nanoparticles (NPs) with appropriate surface modification are of great interest in optical, magnetic and biomedical applications because of the unique combination of the nanoscale magnetic core and the functional shell. In special, gold (Au) coated magnetic NPs with high magnetic moment can be more efficiently stabilized and functionalized through the well-developed Au-S chemistry. Several methods have been developed to synthesize Fe3O4/Au composites attempting to control the particle size, shape, and surface properties [1]. In this work, we present the structural, microscopic, magnetic and hyperfine properties of Au-coated magnetite (Fe3O4) NPs. The uncoated Fe3O4 NPs were synthesized by the co-precipitation method and the gold coating was obtained by adding the gold precursor directly to the boiling solution of sodium citrate with the Fe3O4 NPs. The X-ray diffraction (XRD) data analysis confirms the formation of the spinel structure and Fe3O4 NPs with a mean crystallite size of ~8 nm. The XRD pattern of Au-coated Fe3O4 NPs shows extra peaks consistent with the formation of the gold phase. The mean particle size has been determined from high-resolution transmission electron microscopy images, which corroborates the mean crystallite size of the Au-coated Fe3O4 NPs. The saturation magnetization determined from magnetization vs. magnetic field curves for the uncoated NPs suggests the occurrence of magnetic disorder likely at the particles surface. However, the saturation magnetization increases for the Au-coated NPs which suggests that the gold coating partially reduces the magnetic disorder. Zero-Field-Cooled and Field-Cooled curves show features associated with a thermal blocking process of interacting particles. The decrease of the blocking temperature from TB= 119 K to 95 K after the gold coating suggests the weakening of the particle interactions. Room temperature Mössbauer spectrum shows features related to thermal relaxation of interacting magnetic moments in agreement with the DC magnetization results. Moreover, at 77K the Mössbauer spectra are well resolved using magnetic sextets, which are assigned to the Fe ions occupying tetrahedral and octahedral sites at the core and shell parts of the particle. Figure 1. The Rietveld refinement of the XRD patterns of the gold-coated Fe3O4 nanoparticles. The observed and calculated data are represented by the points and solid line, respectively. The Bragg reflections are also indicated. The HRTEM of the gold-coated Fe3O4 nanoparticles is shown in the inset. References [1] Oscar A. Loaiza, Elena Jubete, Estibalitz Ochoteco, German Cabañero, Hans Grande, Javier Rodriguez, Biosensors and Bioelectronics, 26 (2011) 2194–2200.
  • 90.
    T08 LOW TEMPERATUREMÖSSBAUER STUDY OF Fe DOPED ZnO Ligia E. Zamora1, J. F. Exp Ajus Distri Fe2+ Fe3+ 20K 86 Piamba1, J. A. Tabares1 and G. A. Pérez-Alcázar1 1Grupo de Metalurgia y Teoría de Transiciones de Fase, Facultad de Ciencias, Universidad del Valle. Cali, Colombia. *Corresponding author: e-mail: ligia.zamora@correounivalle.edu.co Keywords: Fe doped ZnO, Ferromagnetic, Semiconductor, Mössbauer. Topic:T08- Magnetism and Magnetic Materials The Zn0.90Fe0.10O system was prepared by mechanical alloying at 24 h. The structural characterization of the sample was performed by X-ray diffraction and the pattern showed the würtzite structure of ZnO; and the bcc structure of α-Fe. The hyperfine parameters were obtained from Mössbauer spectroscopy. The Mössbauer spectra at room temperature shows that the samples present three components: a ferromagnetic, associated to Fe phase; and two paramagnetic, associated to the Fe atoms, which penetrate inside the ZnO matrix behaving as Fe3+ and Fe2+. The sample was cooled to 20 K and spectra were taken at different temperatures. The Magnetic properties were investigated with Vibrating Sample Magnetometer (VSM) at room temperature, which detected a ferromagnetic behavior, with coercive field of 330 Oe. The behavior of resistivity was measured as a function of temperature. Figure 1 shows the temperature dependence of normalized resistivity for ZnO in the range 20 to 300K. Also, it presents a peak at 50 K, which is associated to a magnetic transition. 0 50 100 150 200 250 300 1,0 0,8 0,6 0,4 0,2 0,0 Temperature (K) 24h R/Rmax Figure 1. Temperature resistivity normalized by Zn0.90Fe0.10O Mössbauer spectra were collected decreasing the temperature, in Figure 2 the spectrum is shown at 20K; the other spectra are similar. In Figure 3 is showed the behavior of the mean hyperfine field obtained from the fitting the spectra. 1,00 0,98 -9 -6 -3 0 3 6 9 V (mm/s) Figure 2. Mössbauer spectra at 20K for Zn0.90Fe0.10O
  • 91.
    Distribution 0 100200 300 87 340 335 330 325 <Bhf> Temperature (K) Figure 3. Mean Hyperfine Field as a function of temperature for Zn0.90Fe0.10O From the fit of the spectra the mean hyperfine magnetic field, Bhf, versus temperature was obtained and illustrated in figure 3. It is observed a kink at 50 K, which is associated to a reentrant spin glass- ferromagnetic transition (1), in according with results obtained in Resistivity. Distribución 0 100 200 300 340 335 330 325 <Bhf> Temperatura (K) Distribución 0 100 200 300 340 335 330 325 <Bhf> Temperatura (K) References [1] J. E. Ramos, M. Montero-Muñoz, J. A. H. Coaquira, and J.E. Rodrígez-Páez. Journal of Applied Physics 115, 17E123 (2014).
  • 92.
    T08 MAGNETIC ANDSTRUCTURAL EVOLUTION OF Nd2Fe14B NANOPARTICLES 88 8j1 16k1 8j2 Nd1.1Fe4B4 Pure 10% Co Relative Transmision 20% Co 25% Co -10 -5 0 5 10 Velocity [mm/s] DOPED WITH Co DURING SURFACTANT‐ASSISTED BALL‐MILLING J. S. Trujillo Hernandez1*, J. A. Tabares1 and G.A. Pérez Alcázar1 1Departamento de Física, Universidad del Valle, Meléndez, A. A. 25360, Cali, Colombia. *Corresponding author: e-mail: trujillohernandezjuansebastian@gmail.com Keywords: Mössbauer Spectrometry, X-ray Diffraction, Vibrating Sample Magnetometry, NdFeB magnets. Topic: T08- Magnetism and Magnetic Materials In the search of novel nanosized magnetic materials with enhanced magnetocrystalline anisotropy and energy product, the study of rare-earth based nanostructures is becoming more intense. Materials with large coercivity like Nd2Fe14B improve their physical properties in the nanoscale and may be coupled with other magnetically softer compounds such as α-Fe or Fe3B to fabricate high-performance permanent magnets at a lower cost [1]. However, chemical methods, used in the synthesis of various magnetic nanoparticles, have a limited success in the case of complicated hard phase rare-earth compounds [2]. High-energy ball-milling is a simple, inexpensive and efficient method for size reduction of particle size of nanocrystalline powders. In this work, powder produced by arc melting of the alloy Nd16(Fe76-x Cox)B8 with x = 0, 10, 20 and 25 (size distribution under 20 μm) was milled in a high-energy planetary ball-mill (Fritsch Pulverisette 5 with hardened steel balls) at a rotational speed of 300 rpm. The milling was performed in a protective argon atmosphere with the ball-to-powder weight ratio of 20/1 for milling times varying from 1 to 2 h. Hexane (55% of powder weight) was introduced in the mill as a solvent together with oleic acid (12% of powder weight) as surfactant. The powders obtained after milling was washed with ethanol. X-ray diffraction (XRD), Mossbauer spectroscopy (MS), and Vibrating Sample Magnetometry (VSM) measurements were performed in order to characterize the properties of the obtained samples. A PanAnalytical diffractometer with a Cu anode, a constant acceleration mode Mössbauer spectrometer with a 25 mCi 57Co (Rh) source, and a PPMS of Quantum Design were used, respectively, to obtain these measurements. Figure 1 shows the Mössbauer spectra for the above mentioned compositions. Mössbauer Spectrometry shows the ferromagnetic behavior (seven sextets) associated to the soft and hard magnetic phases and one paramagnetic component (doublet) associated to the minority Nd1.1Fe4B4 phase. All samples present a hard magnetic behavior. The increase of Co content in these samples does not improve the hard magnetic behavior. Figure 1. MS for samples at different concentration of Co. Seven magnetic sites and a doublet need to be included.
  • 93.
    Figure 2. AFMimage (500nm x 500nm) of the Nd2Fe14B doped with Co. References [1] E. F. Kneller and R. Hawig, IEEE Trans. Magn. 27 (1991) 3588.E. [2] Ruiz Saldarriaga, Thesis: Efecto de altas concentraciones de níquel en las propiedades magnéticas y estructurales de la aleación Nd16Fe76B8.. This work was partially financed by “Centro de Excelencia de Nuevos Materiales CENM-Univalle. 89
  • 94.
    T08 MAGNETIC BEHAVIOROF THE FeSi (sc) PHASE WITH TEMPERATURE 90 VARIATION J. F. Piamba1*, G.A. Pérez Alcázar1 1Departamento de Física, Universidad del Valle, A.A. 25360, Cali, Colombia. *Corresponding author: e-mail: jeferson.piamba@correounivalle.edu.co Keywords: Mössbauer spectroscopy, FeSi (sc), XRD. Topic: T08- Magnetism and Magnetic Materials. Binary alloys have been widely studied, principally Fe-Si alloys [1, 2, 3], which present the FeSi simple cubic (sc) ordered structure with a paramagnetic behavior [4]. In this work we present the study of Fe50Si50 system prepared by melting and heat treatment. This process was utilized to obtain the sc crystalline structure with high structural order. X-ray diffraction found that the system present a FeSi mono-phasic sc structure, with crystallite size 138.9±0.5 (nm), lattice parameter 4.490±0.003 (Å) and high structural order, evidenced by the presence of super structure lines. Fig. 1 shows the XRD pattern of the prepared sample, in which the most intensive super structure line corresponds to the diffraction of the (312) family planes. This indicates that the sample presents a high structural order, and that the melting and heat treatment were appropriated. Exp. Adj Bkg FeSi(sc) 20 40 60 80 Intensity (a.u.) 2 º (312) Figure 1. XRD pattern of Fe50Si50 sample obtained by melting and heat treatment. Scanning electron microscopy (SEM) showed that the melting process generated an uniformity and homogeneity of material. The hysteresis loop result shows that the sample has a coercive field Hc = 25.9 ± 0.2 (Oe) classifying it as magnetically soft and that the predominant interaction inside the material is dipolar, main feature used in magnetic recording devices. Mössbauer spectroscopy results showed that the samples exhibit in the whole range of measure temperatures a paramagnetic behavior (see Fig. 2a). Although there is no change in the magnetic behavior of the system, their hyperfine parameters vary, as seen in Fig. 2b. It can be observed an increase of IS and QS with decreasing of temperature. 20K 120K -4 -2 0 2 4 Relative Transmission 300K V (mm/s) (a) 0.8 IS 0 50 100 150 200 250 300 0.6 0.4 0.2 QS IS, QS (mm/s) Temperature (K) (b) Figure 2 Mössbauer spectra (a) and behavior of hyperfine parameters of the FeSi phase as a function of Temperature. The soft magnetic behavior detected by VSM measurement contrast with the paramagnetic behavior detected by Mossbauer and this is explained by the nanostructured character of the sample, in which the atoms of the surface and of the boundary lost its coherence and can behave as ferromagnetic.
  • 95.
    References [1] A.García Escorial, P. Adeva, M.C. Cristina, A. Martín, F. Carmona, F. Cebollada, V.E. Martín, M. Leonato, and J.M. González, Mater. Sci. Eng. A 134 (1991) 1394. [2] E. Gaffet, N. Malhoureux, and M. Abdellaoui., J. Alloys Compds., 194 (1993) 339 [3] Z.B. and S.T., Acta Materialia, 53 (2005) 1233 [4] J. F. Piamba, R. R. Rodríguez, and G.A. Pérez Alcázar, Rev. Mex. Fis. S57 (2) (2012) 88 91
  • 96.
    T08 MAGNETIC BEHAVIOROF TWO SPHERICAL NANOPARTICLES WITH DIPOLAR 92 INTERACTION AND INTERNAL ISING INTERACTIONS A.M. Schönhöbel1,* and W. R.Aguirre-Contreras1 1Grupo de Metalurgia y Transiciones de Fase, Facultad de Ciencias Naturales y Exactas, Universidad del Valle. Cali, Colombia *Corresponding author: e-mail: ana.schonhobel@correounivalle.edu.co Keywords: Hard spherical nanoparticles, Monte Carlo simulation, Metropolis algorithm, dipolar interaction, exchange interaction Topic: T08- Magnetism and Magnetic Materials Using a three-dimensional Ising model and Monte Carlo simulations by Metropolis algorithm, we have studied the temperature-dependent magnetization of two ferromagnetic and antiferromagnetic nanoparticles on a body-.centered cubic lattice. We have considered identical nanoparticles with spherical geometry and they are interacting via dipolar forces. The effect of dipolar forces and the exchange couplings on the critical behavior are investigated. Our results present rich critical behavior, which include Paramagnetic-Ferromagnetic phase transitions. It is also found that nanoparticles size and the dipolar force between them are related with the appearance of more than a unique critical point. References [1] N. N. Phuoc, T. Suzuki, R. W. Chantrell and U. Nowak. Phys. stat. sol. (b). V 244 (12) (2007) 4518 [2] E. De Biasi, C.A. Ramos, R.D. Zysler, D. Fiorani. Physica B. V 372 (2006) 345 [3] A. Weizenmann and W. Figueiredo. Int. Journ. of Mod. Phys. C. V. 23 (08) (2012) 1240006–1 [4] A. Weizenmann and W. Figueiredo. Phys. A, 389:5416, (2010). [5] K. Trohidou and M. Vasilakaki. Acta Phys. Polonica A. V. 117 (02) (2010) 374
  • 97.
    T08 MAGNETIC ORDERSTUDY OF THE INTERMETALLIC FeGa3‐xGex SINGLE 93 CRYSTALS BY MÖSSBAUER SPECTROSCOPY J. Munevar1,2, H. Micklitz1, E. M. Bittar1, M. Cabrera-Baez2, M. A. Avila2, R. Ribeiro2, Y. J. Uemura3, E. Baggio- Saitovitch1 1Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil. 2) Departamento de Fisica, Universidade Federal do ABC, Santo Andre, Brazil 1Department of Physics, Columbia University, USA *Corresponding author: e-mail: munevar@cbpf.br Keywords: Intermetallic compounds, quantum critical point Topic: T08- Magnetism and Magnetic Materials The study of the magnetic semiconducting materials has gained attention due to their potential technological applications, besides the new physics involved. The FeGa3 compound is a very well known semiconductor with an energy gap of about 0.5 eV, caused by a hybridization between the Fe d and the Ga p states [1]. Doping with electrons via chemical substitution of the Ga by Ge leads to a change in the magnetic order, going from diamagnetism to ferromagnetism, reaching transition temperatures as high as 80 K. The purpose of this work is to study the magnetic properties via magnetization measurements and Mossbauer spectroscopy, where spectra for different compositions and at different temperatures and external fields were obtained. For samples showing Ge concentration below 0.13, there is no magnetic order as expected, and uSR measurements show an increase in the relaxation rate only at very low temperatures. Above this concentration, antiferromagnetic order is observed at low fields, and for fields as high as 1kOe is observed a ferromagnetic order. We also observe the magnetic behavior from Mossbauer spectroscopy, and a thorough analysis for spectra with zero field and external field will be presented. These results confirm the onset of magnetic correlations for doping above the value reported close to the quantum critical point. It is also indicating that exists some correlations between Fe moments induced by the substitution, either by adding more electrons to the Fermi surface or by the distortion of the lattices. A discussion about the nature of the ferromagnetic order will be presented. References [1] K. Umeo, Y. Hadano, S. Narazu. T. Onimaru, M. A. Avila, T. Takabatake, Phys. Rev. B textbf{86}, 144421 (2012).
  • 98.
    T08 MAGNETOTRANSPORT PROPERTIESOF (Fe AND Ni)‐DOPED In2O3 POWDERS 94 OBTAINED BY SOLID STATE REACTION METHOD L.C. Sánchez1*, O. Arnache2, C. Ortega1, L.A. López1 and L. Ensuncho1 1Grupo Avanzado de Materiales y Sistemas Complejos-GAMASCO, Universidad de Córdoba, Montería - Colombia. 2Grupo de Estado Sólido, Instituto de Física, Calle 70 No. 52-21, A.A., , Universidad de Antioquia - UdeA, Medellín- Colombia *Corresponding author: e-mail: luiscarlos@correo.unicordoba.edu.co Keywords: Indium oxide nanoparticles; Transition metal doped; Solid State Reaction Method. Topic: T08- Magnetism and Magnetic Materials Indium Oxide (In2O3) is a transparent and dielectric material with a direct band gap of 3.75 eV, which has a wide variety of technological applications.. During recent years, the doping mechanism by transition metal (TM) impurities in In2O3 is considerably attractive due to its integration of physical properties (optical, electronic and magnetic) into one single material. This class of materials are called diluted magnetic semiconductors – DMS (or semimagnetic semiconductors). From viewpoint of magnetism, DMS system have attracted great interest for fundamental research and applications due to coexistence of high temperature magneticsm and semiconducting properties. The origin of ferromagnetism in TM-doped semiconductors has been controversial and has been explained by different mechanisms such as carrier-mediated interaction. However, in semiconductors with low carrier densities such as oxides, the novel type of magnetism can be explained by magnetic polaron mechanism. In this model, the spins of magnetic dopants incorporated into the semiconductor lattice interact through a donor-impurity band, formed by lattice defects such as oxygen vacancies. Coey et al.[1] explain the spin alignment of the 3d transition-metal cations by the coupling of their spins, which are antiparallel to the spin of donor electrons. Because of this coupling, all spins within this expanded orbit are aligned. Because of the overlap of different orbits, an impurity band is formed, aligning a huge number of 3d magnetic spins parallel, resulting in ferromagnetism. In the framework of this theory, not only the dopant concentration but also the number of donor electrons must be quite large to obtain ferromagnetism. Experimentally, there is much indirect evidence that the ferromagnetism is related to defects [2]. In this work In2-xTMxO3 (TM=Fe and Ni) polycrystalline samples with x=5% were prepared by a conventional solid state reaction method. Starting materials of In2O3 , Fe2O3 , α-Fe and NiO of high purity. Two different sources of Fe were used in order to obtain the Fe-doped In2O3. The appropriate amounts of powders were first weighted and mixed by milling for 10 h in a planetary ball mill, then sintered at 900 °C for 12 raising the temperature slowly in a controlled furnace in an air atmosphere. After that, the reacted material was ground in a mortar, pressed into rectangular shaped pellets and fired at 1100 °C for 12 hours. Phase purity and structural parameters were analyzed by means of x-ray diffraction (XRD) analysis technique. Structure refinements were carried out employing Rietveld analysis using Fullprof software. The refinement results confirm that Fe and Ni ions preferentially occupy the In3+ sites in all doped samples. Magnetic properties as a function of temperature at ZFC and FC from 5 to 300K of the pellets were measured by using VSM option in a Physical Properties Measurement System (PPMS, Quantum Design). Room temperature 57Fe Mössbauer Spectroscopy to probe the local magnetic environment prevailing around the Fe sites and also to determine the oxidation state of Fe in the In2O3 matrix have been recorded. Finally, to understand the magneto-transport correlations in those semiconductors we present a discussion of the electrical resistivity and Hall effect properties. References [1] J. M. D Coey, M.Venkatesan, C. B. Fitzgerald, Nat. Mater. 4 (2005) 173. [2] R.K. Singhal, A. Samariya, Sudhish Kumarb, S.C. Sharma, Y.T. Xing, U.P. Deshpande,T. Shripathi, E. Saitovitch, Appl. Surf. Sci. 257 (2010) 1053.
  • 99.
    T08 STUDY OFMAGNETIC AND STRUCTURAL PROPERTIES DURING DEPOSITION OF 95 THIN FILMS TB0.257FE0.743. D. A. Granada1, Y. A. Rojas1, H. Rodríguez1, D. Oyola Lozano1, D. Betancourth1. 1 Laboratorio de Ciencia de Materiales y Tecnología plasma, Universidad del Tolima- Barrio Santa Helena - Ibagué, Colombia *Corresponding author: e-mail: dalagranada@gmail.com; dagranadar@ut.edu.co. Keywords: Stainless steel, point defects, CXMS Topic: T08- Magnetism and magnetic materials. The amorphous alloys of rare earth and transition metals (TR-MT), are of great interest to study the influence of structural disorder and the content of the TR in the basic magnetic properties. It is known that the exchange interactions between TR and MT originate a parallel or anti-parallel alignment of the moments of the TR with the time of MT, and the structural disorder can be caused by heat treatment during the preparation of alloys or substrate temperature during deposition of the films [1]. In the present study the influence of the substrate temperature on the magnetic and structural properties of thin films are reported Tb0.257Fe0.743 composition grown by DC sputtering on glass substrates.The substrates are subjected to temperatures of 100K, 300K and 500K. Structural properties from Diffraction Rays x (see fig.1) were investigated, the magnetic properties were investigated by Mössbauer spectroscopy at room temperature, View (fig.2). The Mössbauer spectra identified that increases in temperature increased quadrupole interactions giving greater paramagnetic character indicating the contribution of Tb to Fe environment. From the hysteresis loop of each film depending on the temperature of 5K, 80K and 300K View (fig.3); identified that the thin films are magnetically soft to very narrow hysteresis cycles, which have values of coercive fields from 5OE to 250Oe. Also, it was observed that the increase of the substrate temperature during deposition of the thin films will increase the degree of crystallinity. 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 9 0 0 0 8 0 0 0 7 0 0 0 6 0 0 0 5 0 0 0 4 0 0 0 3 0 0 0 2 0 0 0 1 0 0 0 intensity(U.A) 2  T e m p . = 1 0 0 K T e m p . = 2 0 0 K T e m p . = 3 0 0 K T e m p .= F it. T b N T b F e Fig.1. Pattern Diffraction Rays x, to thin films at 100K, 300K and 500K. -10 -8 -6 -4 -2 0 2 4 6 8 10 1,004 1,002 1,000 0,998 0,996 1,002 1,000 0,998 1,004 1,002 1,000 0,998 0,996 0,994 exp total fit1 Temp. 100K 0,996 Temp. 300K exp total fit1 0,994 Temp. 500K exp total fit1 Relative Transmission V [mm/s] Fig.2. Mössbauer Spectroscopy, to thin films at 100K, 300K and 500K.
  • 100.
    -20000 0 20000 96 50 0 -50 -2 0 0 0 0 2 0 0 0 0 M (emu/g) H (O e ) 9 K 9 0 k 3 0 0 K M (emu/g) H (Oe) 100K 300K 5 0 0 K Fig. 3. Hysteresis Loops, of thin films of 100K, 300K and 500K, taken at a temperature of 80K. References [1] Malmhal R. l. (1987). Low-noise terbium-doped fibre amplifier operating at 1.54μm. Journal Appl. Phys 23: 1026-1028.
  • 101.
    T08 STRUCTURAL, MAGNETICAND MECHANICAL HARDNESS CHARACTERIZATION OF THE ALLOY Nd16 (Fe76‐x Nix) B8 WITH x = 0, 10, 20 AND 25 Observed Calculated Pure 10% N i 20% N i 25% N i 20 30 40 50 60 70 80 90 2  [Degrees] 97 J. S. Trujillo Hernandez1 J. A. Tabares1*, E. Ruiz Saldarriaga1, L. Zamora1, W. Aguirre1 and G.A. Pérez Alcázar1 1Departamento de Física, Universidad del Valle, Meléndez, A. A. 25360, Cali, Colombia. *Corresponding author: e-mail: jesus.tabares@correounivalle.edu.co Keywords: Mössbauer Spectrometry, X-ray Diffraction, Vibrating Sample Magnetometry, NdFeB magnets. Topic: T08- Magnetism and Magnetic Materials The compound of neodymium-iron-boron Nd2Fe14B approximate formula provided the best combination of magnetic and thermal properties of permanent magnets. Furthermore the Nd2Fe14B is surrounded by a magnetically soft material, for example α-Fe or Fe3B, showing an increase in the magnetic remanence caused by the exchange interaction between the two phases. This exchange interaction between the two phases occurs when the size of the phases is in the nanometer scale, of the order of 20 nanometers. Previous work [1] suggest alloy system Nd16 (Fe 76-x Nix) B8 allows to get the Nd2Fe14B as majority phase with nanometer size. In this work, samples of the alloy Nd16 (Fe 76-x Nix) B8 with x = 0, 10, 15, 20 and 25 were produced by arc melting and heat treated at 1073 K during 30 minutes and then quenched in ice water mixture. X-ray diffraction (XRD) (PanAnalytical, Cu anode), Mossbauer spectroscopy (MS) (constant acceleration mode with a 25 mCi 57Co (Rh) source) and Vibrating Sample Magnetometry (VSM) (Quantum Design, PPMS) were used in order to characterize the properties of the obtained samples. Microhardness tests were performed too. Figure 1 shows the XRD patterns for nickel varying concentrations. The system presents the hard Nd2Fe14B and the Nd1.1Fe4B4 phases for samples with x = 0, 10 and 20. When concentration increases to x = 10, 20 and 25 the NdNi2 and Nd2O3 phases appears. Crystallite size ranged between 10 to 100 nm. Figure 2 shows the Mössbauer spectra for the above mentioned compositions. There are seven sextets associated to the soft and hard magnetic phases and one doublet associated to the minority Nd1.1Fe4B4 phase, just identified by XRD. Magnetometry results allowed establish all samples present a hard magnetic behavior. The increase of Ni content in these samples does not improve the hard magnetic behavior but decrease the crystallite size of the hard phase. All samples improved hardness with increasing Ni. Intensity [a.u.] Figure 1. XRD patterns varying Ni concentrations. Pure sample pattern is include too.
  • 102.
     j1 Fe 25% N i Figure 2. MS for samples at different concentration of Ni. Seven magnetic sites and a doublet need to be included. References [1] E. Ruiz Saldarriaga, Thesis: Efecto de altas concentraciones de níquel en las propiedades magnéticas y estructurales de la aleación Nd16Fe76B8 [2] Rajasenkhar M., Akhtar D., Raja M. M. and Ram S., J. Magn. Magn. Mater., 320, (2008) 1645-1650. [3] Dai S., Morrish H., Zhou X. Z., Hu B. P. and Zhang S. G., J. Applied Physics, 63, (1988) 3722. This work was financially supported in part by “Centro de Excelencia de Nuevos Materiales CENM-Univalle. 98  k1  j2 Nd1 .1Fe4B 4 Pure 10% N i Relative Transmission 20% N i -10 -5 0 5 10 Velocity [mm/s]
  • 103.
    T08 STUDY OFMAGNETIC PROPERTIES OF THE Mn3O4 MAGNETIC COMPOSITES 99 FOR APPLICATION IN WASTEWATER TREATMENT Isabel Cristina Souza Dinóla1, Gabriela Cordeiro Silva2 1 FUCAPI- Manaus -Amazonas 2 –Cefet – Belo Horizonte - Minas Gerais Composites with magnetic properties have been synthesized by means of the deposition of manganese oxide, Mn3O4, precipitated by using O2, onto magnetic particles. The magnetic particles in the composites form agglomerates with Mn3O4 particles. Solid-liquid separation by means of the application of the magnetic field is possible. The application of the magnetic composite in the oxidative adsorption of As3+ was evaluated. During the Arsenic oxidation-adsorption process, iron is not released and part of the Mn (II) released to solution is being adsorbed or precipitated, or both, which implies in a less contaminants release to solution. The general aim of the present work is to study the Mn3O4 magnetic composites in the application in wastewater treatment using several spectroscopic techniques like Mossbauer and Raman techniques to investigate the oxidation states of this composite improving our knowledge about the arsenic interactions with Mn3O4.
  • 104.
    T08 SYNTHESIS ANDCHARACTERIZATION OF MAGNESIUM FERRITES 100 NANOPARTICLES L. León Félix1, J. Mantilla1, M. A. R. Martinez1 and J. A. H. Coaquira1 1Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília, DF 70910-900, Brazil. *Corresponding author: e-mail: lizbetlf@gmail.com Keywords: Magnesioferrite, Mössbauer spectroscopy, sol-gel method. Topic: T08- Magnetism and Magnetic Materials Magnesium ferrite (MgFe2O4) is one of the most important members of the spinel family. Because of its small magnetocrystalline anisotropy, the superparamagnetic properties are still present at relatively low temperatures and/or high magnetic fields. MgFe2O4 is a n-type semiconducting material and apart from the magnetic and electronic applications, it has been widely applied in catalyst and sensors technology [1]. In this work, we present the study of MgFe2O4 nanoparticles (NPs) synthesized by colloidal suspension of magnesium nitrate hexahydrate (Mg(NO3)2.6H2O) in gelatin solution and using the sol–gel method. After the gel formation, the samples were annealed for 4 h at 350, 450, 550 650 and 850°C in air atmosphere. The X-ray diffraction (XRD) data analysis confirms the formation of only the spinel type structure of MgFe2O4 NPs. The mean crystallite size shows an increase by increasing the annealing temperature from 8 to 28 nm. The mean particle size has also been obtained from high-resolution transmission electron microscopy images, which corroborates the mean crystallite size. The Mössbauer spectroscopy measurements of MgFe2O4 NPs were performed at 77 K and room temperature. Room-temperature Mössbauer spectra of samples annealed at temperatures below 550°C show only a central doublet which suggests the occurrence of a superparamagnetism. However, Mössbauer spectra of samples annealed with temperatures above 650°C show a central doublet and collapsing sextets revealing the occurrence of the thermal relaxation of magnetic moments. At 77 K, Mössbauer spectra of samples annealed at temperatures below 550°C show also the presence of a central doublet and collapsing sextets. However, Mossbauer spectra of samples annealed at temperatures above 650°C show well defined sextets which evidence that the thermal relaxations effects observed at higher temperatures are no longer present. Figure 1. Room temperature XRD patterns of MgFe2O4 samples calcinated at different temperatures. The observed and calculated data are represented by the points and solid line, respectively. The Bragg reflections are also indicated. References [1] Zhengsong Lou, Minglong He, Ruikun Wang, Weiwei Qin, Dejian Zhao, and Changle Chen, Inorg. Chem. 2014, 53, 2053−2057.
  • 105.
    T08 SYNTHESIS ANDCHARACTERIZATION OF MAGNETIC FLUID CoFe2O4 WITH 101 OLEIC ACID AND TWEEN 80 J. L. López1, C. Carioca Fernandes1, J. H. Dias Filho2, R. Paniago3 and K. Balzuweit3 1Centro de Ciências Biológicas e da Natureza, Núcleo de Física, Universidade Federal do Acre, Rio Branco, AC 69915-900, Brazil. 2) Departamento de Ciências Exatas, Universidade Estadual de Montes Claros, 39.401-089, Minas Gerais, Brazil. 3) Departamento de Física, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Brazil. *Corresponding author: e-mail: jorge0503@gmail.com Keywords: Magnetic Nanoparticles, CoFe2O4, Topic: T08- Magnetism and Magnetic Materials CoFe2O4 magnetic nanoparticles were prepared by co-precipitation from FeCl36H2O and Co(NO3)26H2O aqueous solutions using NaOH and methylamine as precipitating reagents. The nanoparticles have an average size of 10 and 7 nm and exhibit superparamagnetism at room temperature. The nanoparticles were used to prepare a water-based magnetic fluid using oleic acid and Tween 80 as surfactants. The morphology, structure, magnetic properties and composition of CoFe2O4 magnetic nanoparticles coated with oleic acid and Tween 80 were examined. The stability and magnetic property of the magnetic fluid were also characterized. Aqueous samples were studied by Mössbauer spectroscopy and magnetic susceptibility in the range of 4.2–250 K. The saturation magnetization (Ms) at 4.2 K was determined from M vs 1/H plots by extrapolating the value of magnetizations to infinite fields, to 20 and 25 emu/g in both samples and coercivity to 50 and 65 Oe, respectively. The low saturation magnetization values were attributed to spin non-collinearity predominantly at the surface [1]. From the magnetization measurements a magnetic anisotropy energy constant (K) of 2.5×105 and 4×105 J/m3 were calculated. CoFe2O4 spectra at room temperature showed a doublet due to superparamagnetic relaxation and two sextets at low temperature for the sample with the smaller diameter. The sample shows a larger-diameter lower relaxation spectrum at room temperature. The line form in spectra Mössbauer vary with the temperatures it was simulated using a model of superparamagnetic relaxation of two levels (spin ½) and theory stochastic [2]. We assume for the particle diameters a probability distribution function of log-normal type and it was taken into account a dependence of the magnetic transition temperature on particle diameter. References [1] J. L. López, H. –D. Pfannes, R. Paniago, J.P. Sinnecker, M.A. Novak, J. Magn. Magn. Mater, 320 (2008) e327. [2] H.-D.Pfannes, J.H.Dias Filho, R. Magalhães Paniago, J. L.López, R. Paniago, Brazilian Journal of Physics, 31 (3), (2001) 409.
  • 106.
    T08 SYNTHESIS, STRUCTURALAND MÖSSBAUER SPECTROSCOPY 140 120 100 80 60 40 20 Exp. data Ajuste to 2 sextetos 1 sexteto 2 sexteto 102 CHARACTERIZATION OF NiFeO3 Nanoparticles J. Mantilla1,2, L. León Félix1, V.K. Grag1, A.C. de Oliveira1, J. A. H. Coaquira1 1Universidade de Brasília, Instituto de Física, Núcleo de Física Aplicada, Brasília, DF, CEP 70910-900. 2Laboratorio de caracterización de muestras, Facultad de Ciencias Escuela de Fisica, Universidad Central de Venezuela *Corresponding author: e-mail: mantilla52@gmail.com Keywords: Nanoparticles; Superparamagnetism; Surfactant; Sol-Gel Topic: T08- Magnetism and Magnetic Materials In this work, we present the study of NiFeO3 nanocrystalline syntnthesized by sol gel (critrate method) with calcining temperature of 600°C for 6 h [1]. The structural properties and crystallite sizes are determined by X-ray diffraction (XRD) technique. The hyperfine properties are characterized by Mössbauer spectroscopy and using Transmission Electron Microscopy (TEM) images was determined the size and size distribution of prepared particles. The X-diffraction pattern of the calcined powder was synthesized using this route and it shows that the final product is NiFeO3 with the cubic perovskite structure. The size of particles was determined by Scherrer formula. The average size were found to be 43, 5 nm. 20 30 40 50 60 70 0 Relative frenquecy (%) Particle size (nm) Do = 39.4 nm  = 0.28 Figure1. (a) TEM images of NiFeO3: scale bar 0,250 μm. (b) particle size distributions measured from TEM images The Fig. (1.a) shows the TEM images of NiFeO3 nanoparticles calcined at 600°C and the distribution of these nanoparticles are shown in the Fig. (1.b). The distribution seems to be symmetric (Gaussian) about 39,4 nm. The Mössbauer spectroscopy measurements of NiFeO3 nanocrystalline were performed at 77 K and room temperature as shown Fig (2). The Mössbauer spectras in Fig. 2 were well-fitted with two sextet. Table I shows the results of the hyperfine parameters corresponding Mössbauer spectra In the spectras are observed the presence of a well-developed magnetic order presenting with slightly asymmetrical lines due the existence of different magnetic environments Fe positions within the perovskite structure. T=297 K NiFeO3 T=77 K -10 -5 0 5 10 Relative transmission (a.u.) Velocity (mm/s) Figure 2. 57Fe Mössbauer spectra of NiFeO3 performed at 298 K and 77 K
  • 107.
    Table I: Mössbauerhyperfine parameters: hyperfine field Bhf, isomer shift δ and quadrupole shift QS for sample. 103 Structure Temp. (K) Bhf (T) IS (mm/s) QS (mm/s) NiFeO3 298 52,08 0,36 -0,01 48,63 0,24 -0,01 77 54,9 0,47 -0,01 50,87 0,35 -0.01 References [1] Brinker C.J and Scherer G.W. Sol-Gel Sciences the Physics and chemistry of Sol-Gel processing. Academic Press, San Diego 1990.
  • 108.
    T10 57Fe‐MӦSSBAUER STUDYOF IRON‐CONTAINING SODA LIME ALIMINOSILICATE GLASS WITH VISIBLE‐LIGHT ACTIVATED PHOTOCATALYTIC EFFECT -10 -5 0 5 10 Velocity / mm s -1 Fig.1 FeMS of heat-treated 50NCFS8A glass 104 Y. Iida, S. Kubuki, K. Akiyama and T. Nishida 1 Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachi- Oji, Tokyo 192-0397, JAPAN 2 Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering, Kinki University, Kayanomori 11-6, Iizuka, Fukuoka 820-8555, JAPAN *Corresponding author, e-mail: kubuki@tmu.ac.jp Keywords: photocatalyst, soda lime aluminosilicate glass Topic: T10- Catalysis, Corrosion and Environment 1. Introduction Anatase type TiO2 is well known as a photocatalyst which is activated by UV light with the wavelength () of shorter than 388 nm [1]. Recently, visible light activated photocatalysts have been investigated because of the higher effectiveness. Kubuki et al. reported that iron-containing soda lime silicate glass after heat treatment exhibited visible light activated catalytic ability due to precipitated -Fe2O3[2]. On the other hand, it was reported that aluminate glass had light transmitting ability between visible and infrared (IR) region[3]. It is expected that photocatalytic ability of iron-containing soda lime silicate glass might be increased by introduction of Al2O3 due to the high IR transmittance. In this study, we report a relationship between visible-light activated photocatalytic effect and structure of iron-containing soda lime aluminosilicate glass after isothermal heat treatment. 2. Experimental Iron-containing soda lime aluminosilicate glass with the composition of 15Na2O•15CaO•50Fe2O3• (20-x)SiO2•xAl2O3 (in mass%, x = 5~10 abbreviated as 50NCFSxA) was prepared by conventional melt-quenching method. Starting materials of Na2CO3, CaCO3, Fe2O3, SiO2 and Al(OH)3 were well mixed in an agate mortar. The mixture was poured into a platinum crucible and melted 1400 oC for 1 h. Glass samples were obtained by dipping the crucible bottom into ice cold water. The prepared glass was heat-treated at 1000 oC for 100 min. 57Fe-Mössbauer spectra (FeMS) were measured by using 57Co(Rh) and -Fe as a source and a reference, respectively. X-ray diffraction patterns were recorded between the 2of 10° and 80° with sampling range and scan speed of 0.02° and 5° min-1. Cu-K X-ray was generated by setting the voltage and current at 50 kV and 300 mA. Photocatalytic activity of heat-treated 50NCFSxA was evaluated by methylene blue (MB) decomposition test using 10 mL of 20 molL-1 MB aqueous solution and 40 mg of pulverized glass sample. Ultraviolet-visible light absorption spectra (UV-VIS) of MB after the decomposition test were recorded between 200 and 800 nm under irradiation of visible light with the ‘’ between 420 and 750 nm. 100 98 96 94 3. Results and discussion As shown in Fig.1, FeMS of heat-treated 50NCFS8A glass was composed of a paramagnetic doublet with the isomer shift () of 0.22 mm s-1, quadrupole splitting () of 0.79 mm s-1 and absorption area (A) of 47.2 %, and a relaxed sextet with  of 0.35 mm s-1, internal magnetic field (Hint) of 28.7 T and ‘A’ of 52.8 %, respectively. First order rate constant (k) for MB decomposition of heat-treated 50NCFS8A was estimated to be 1.81×10-2 min-1. In our previous study, the smaller ‘k’ of 4.78×10-4 min-1 was obtained for MB decomposition test using heat-treated 50NCFS0A glass, of which FeMS yielded a relaxed sextet with  Hint and ‘A’ of 0.34 mms-1, 37.9 T and 39.7 %, and a sextet with  Hint and ‘A’ of 0.36 mms-1, 51.8 T and 47.9 %, respectively[2]. These results indicate that the magnetic component observed in FeMS of heat-treated 50NCFS8A glass was smaller than that of 50NCFS0A glass. However,
  • 109.
    photocatalytic activity ofthe former was much larger than that of the latter. It can be concluded that introduction of Al2O3 into iron-containing soda lime silicate glass increases the photocatalytic activity due to the enhancement of visible-infrared light transmittance. References [1] A. Fujishima, K. Honda, Nature, 238 (1972) 37-38. [2] S.Kubuki, et al., J. Radioanal. Nucl.Chem, 301 (2014) 1-7 [3] T.Nishida et al., J. Mater. Chem., 7(9), (1997) 1801-1806. 105
  • 110.
    T10 CHARACTERIZATION OFAIR‐OXIDIZED NICKEL DOPED Li2FeSiO4 J.A. Jaén1, M. Castillo 106 Weeks2 1Depto. de Química Física, CITEN, Edificio de Laboratorios Científicos-VIP, Universidad de Panamá, Panamá 2Escuela de Química, Universidad de Panamá, Panamá *Corresponding author: e-mail: juan.jaen@up.ac.pa Keywords: Orthosilicates, Li2FeSiO4, air oxidation. Topic: T10- Physical Metallurgy and Materials Science The effect of ambient air exposure on Li2Fe1-xNixSiO4 (x=0, 0.10, 0.15, 0.20 and 0.3) has been investigated. This material belongs to a family of orthosilicates proposed as potentially cheap cathode materials for large-scale Li-ion batteries. Li2Fe1-xNixSiO4 samples were prepared by the solid-state reaction of Li2SiO3 with FeC2O4·2H2O and Ni(CH3COO)2·4H2O. They consist of crystals of monoclinic structure with (P21/n) symmetry, with some Fe3+ and/or magnetic impurities. Upon exposition to air for more than a year, FTIR results indicate that some amount of Li2CO3 was formed due to lithium removal from the original structure. Figure 1 shows the room temperature Mössbauer spectra of studied samples where it is evident the presence of Fe3+ with Mössbauer parameters QS ~ 0.68 mm/s and IS ~ 0.18 mm/s. These parameters are close to the reported values for fully delithiated LiFeSiO4 [1]. We thus attributed this doublet to partially delithiated orthosilicates Li2-yFe1-xNixSiO4 formed upon oxidation. The presence of Fe3+ negligible in most Mössbauer spectra of short-term air exposure (recently synthesized), is given in a separate contribution to this meeting. It is inferred that the adsorption of oxygen, carbon dioxide and other air components at the surface of the material upon air exposure provokes the lithium extraction leaving a delithiated particle. Segregated lithium form Li2CO3 at the particle surface. The oxidization of Li2Fe1-xNixSiO4 by air oxidation led to a surface change which is deleterious to the electrochemical performance of the cathode material. Figure 1. Room temperature Mössbauer spectra of air exposed Li2Fe1-xNixSiO4 samples for more than a year. References [1] A. Nytén, S. Kamali, L. Häggström, T. Gustafsson and J.O. Thomas, J. Mater. Chem. 16 (2006), 2266–2272.
  • 111.
    T10 Fe‐DOPED DIOPSIDE(CaMgSi2O6) GLASS‐CERAMICS 107 P.S. Bayer1, M. Olzon- Dionysio2, M.J. M. Pires2, D. Olzon-Dionysio2, S. D. de Souza2, J. D. Fabris2, S. de Souza2, W. T. Shigeyosi3 and V.R. Mastelaro1 1 Instituto de Física de São Carlos - Universidade de São Paulo (USP), São Carlos, SP, Brazil 2Universidade Federal dos Vales de Jequitinhonha e Mucuri (UFVJM), Diamantina, MG, Brazil 3Departamento de Física, Universidade Federal de São Carlos (UFSCar), São Carlos, SP, Brazil *Corresponding author: e-mail: maristolzon@hotmail.com Keywords: diopside, glass-ceramic, CaMgSi2O6 Topic: T10- Physical Metallurgy and Materials Science In more recent years, there has been an increasing interest in studying diopside-based ceramics and glass-ceramics, which present various important physical, chemical and biological properties. If it is used as a biomaterial, diopside is bioactive and may directly be bond to the human bone. Consequently, an important application is as dental and bone implant materials, among others, as nuclear waste immobilizers or for bone tissue engineering or even as sealing materials in solid oxide fuel cells. However, only the surface crystallization process occurs on the CaMgSi2O6 glassy sample, and to obtain the diopside material for such applications, the volume crystallization should be somehow promoted, as by using iron, titanium or zirconium oxides as doping agents, which allow obtaining glass-ceramic materials allowing them to be used in implants or dental prostheses. The main purpose of this research is to investigate the role of iron on the volume crystallization of CaMgSi2O6 doped with small amounts (2 – 9 mass%) of Fe2O3. The coordination environment and the oxidation state of iron are being investigated by Mössbauer spectroscopy, at room temperature. The hyperfine parameters (isomer shift; quadrupole splitting, and the relative subspectral areas for Fe2+ and Fe3+ doublets as a function of iron amount are presented in Figs. 1 and 2. It can be observed from Fig.1 that the proportion of Fe2+ is inversely proportional to the total amount of Fe2O3 until 7 mol%, to reach a plateau from then. Fig. 2 shows that isomer shift and quadrupole splitting values are nearly the same for all the samples. 1 2 3 4 5 6 7 8 9 10 80 70 60 50 40 30 20 Fraction (%) Fe2O3, wt% Fe2 Fe3 Figure 1. Fractions of the Fe2+ and Fe3+ doublets 1 2 3 4 5 6 7 8 9 10 2.25 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 Fe2O3, wt% mm/s iso2 iso3 Q2 Q3 Figure 2 Values of isomer shift and quadrupole splitting for the Fe2+ and Fe3+ doublets References [1] K. Otto, W. Wisniewski and C. Russel, Cryst. Eng. Comm15 (2013)6381
  • 112.
    Acknowledgements: To MsAlice Lopes Macedo, graduate student at UFVJM, for her kind help during the collection of Mössbauer data. This work supported by FAPESP and CNPq(Brazil). JDF is indebted to CAPES (Brazil) for granting his Visiting Professorship at UFVJM under the PVNS program and to CNPq for the grant # 305755-2013-7. 108
  • 113.
    T10 MÖSSBAUER ANDKINEMATICAL STUDIES OF MECHANOSYNTHESIZED NiFe2O4 H. Salazar1, C.A. Barrero1,*, 109 K.E. García1, M. Márquez2 1Grupo de Estado Sólido, Instituto de Física, Universidad de Antioquia, Medellín, Colombia. 2Grupo de Mineralogía Aplicada y Bioprocesos, Universidad Nacional de Colombia, Medellín, Colombia. *Corresponding author: E-mail: cbarrero@fisica.udea.edu.co Keywords: Ferrites; Mechanochemical processing; Kinematical modeling, Mössbauer spectrometry. Topic: T10 - Physical Metallurgy and Materials Science. Nickel ferrite, NiFe2O4, belongs to the spinel ferrite family of the MFe2O4 type, in which M is a divalent metal cation. The nanosized version of this family is interesting due to fundamental aspects related with nanomagnetism and also for their diverse potential applications [1]. Nanocrystalline NiFe2O4 has been prepared by several methods, including high energy mechanochemical route [1-3]. Due to the large number of variables involved in a given mechanochemical synthesis, there are many works that can be performed. In fact, by checking the experimental procedure of previously reported works, we notice that no two research groups have used similar machine conditions. Moreover, in none of these works, it is used a kinematical model of the planetary ball milling process to calculate the kinetic energy imparted by the balls to the starting reactants. The cumulative kinetic energy normalized to the powder mass (Ecum) could be a good criterion of comparison of all possible works, because it contains the values of all the machine variables [4]. We have carefully investigated the effect of some machine variables in the formation of NiFe2O4 when it is obtained via high-energy planetary ball milling of a stoichiometric mixture of NiO and α-Fe2O3, by combining both micro-structural and kinematical studies. Two sets of machine conditions, whose variables include angular speed of disc (), ball to powder mass ratio (mb:mp), number of balls (Nb), and duration of the milling (t), were explored. The products of the mechanosysnthesis were micro-structurally characterized by quantitative X-ray diffraction (XRD) using the Rietveld method and by 57Fe Mössbauer spectrometry (MS). For both set of machine conditions, as the milling time increased, the intensities of the Bragg peaks of NiO and hematite decreased differently, whereas those of the spinel phase increased. The production rate of NiFe2O4 by the first set of conditions was very low, however by using the second set and after 50 h of milling, 86 wt. % of this phase was formed. The MS of the samples generally consisted of sextets and doublets, the sextets were associated to micrometric- or nanometric-sized hematite and/or magnetically ordered nano-sized NiFe2O4, whereas the doublet was assigned to superparamagnetic nano-sized NiFe2O4. Finally, the energy transferred to the powders by the balls during milling in a planetary ball mill was calculated by using a kinematical model [5]. According to the model, Ecum of the order of 1,08 x109 J/kg was required to produce 86 wt. % of nickel ferrite when the second set of machine conditions for 50 h was employed. References [1] V. Šepelák, A. Düvel, M. Wilkening, K.-D. Becker and P. Heitjans, Chem. Soc. Rev. 42 (2013) 7507. [2] T.F. Marinca, I. Chicinas, O. Isnard, V. Popescu, J. Am. Ceram. Soc. 96 (2013) 469. [3] S. Bid, P. Sahu, S. Pradhan, Physica E 39 (2007) 175. [4] Gy. Kakuk, I. Zsoldos, A. Csanády and I. Oldal, Rev. Adv. Mater. Sci. 22 (2009) 21. [5] M. Abdellaoui and E. Gaffet, Acta Metall. Mater 43 (1995) 1087.
  • 114.
    T10 MÖSSBAUER CHARACTERIZATIONOF FEED COAL, ASH AND FLY ASH FROM A 110 THERMAL POWER PLANT Maricel Moreno 1, F. Reyes Caballero 1 and S. A. Martínez Ovalle 1 1Grupo de Física Nuclear Aplicada y Simulación, Facultad de Ciencias, Universidad Pedagógica y Tecnológica de Colombia. Tunja, Boyacá, Colombia. *Corresponding author: e-mail: maricel.morenol@uptc.edu.co Keywords: Feed coal, ash, fly ash, thermal power plant, Mössbauer spectroscopy Topic: T10- Physical Metallurgy and Materials Science 57Fe transmission Mössbauer spectroscopy has been used to characterize the iron-bearing minerals in feed coal, ash (up to 750 °C) and fly ashes from a thermal power plant in Boyacá, Colombia. The feed coal sample that was analyzed represents the bulk of coal being fed to the furnace of thermal power plant, Fig.(1). Various samples of high temperature ash (up to 750 °C) were prepared from feed coal. The fly ash was collected from a hopper of the electrostatic precipitator during the same period from feed coal collection, Fig.(2). Pyrite and an iron-containing aluminosilicate phase were the iron-bearing parent minerals observed in the representative sample of feed coal. The fundamental aim of the work was clarify the mechanism of conversion of iron-bearing minerals in feed coal through the process of combustion. -5 0 5 1,000 0,992 Backscattered (n.u) mm/s Figure 1. Mossbauer spectrum of feed Coal. The analysis of this and treated feed coal spectra was done while using spectra of low velocity. -10 0 10 1,00 0,99 0,98 Backscattered [n.u] mm/s Figure 2. Mossbauer spectrum of fly ash. The analysis of this was done while using spectra of low velocity. It can be seen in Fig. (2) the number of phases present in the feed coal remain in the fly ash, showing a change in the phases present initially in feed coal due to oxidation aluminosilicate phase, a magnetic phase appearing associated hematite. This phase transition undergone by the feed coal is exhibited when heated from 500°C so that the intensity ratio decreases proportionally. Discussion wider one arises from the detailed analysis of the Mossbauer parameters of the samples of heated of feed coal since evaluate of process of thermal power plant. References [1] F. Reyes, G. A. Perez Alcázar, J. M. Barraza, A. Bohórquez, J. A. Tabares and N. L. Speziali, Hyperfine Interactions. 148/149: 39-46, 2003. [2] F. Reyes, G. A. Perez Alcázar, J. M. Barraza, A. Bohórquez and J. A. Tabares, Hyperfine Interactions. 148/149: 31- 38, 2003.
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    T10 MÖSSBAUER SPECTROSCOPYANALYSIS OF THE Ar‐51 METEORITE FROM THE 111 MUSEUM OF NATURAL HISTORY‐ LIMA, PERU Cerón Loayza M.L1*, Bravo Cabrejos J.A1. 1 Laboratorios de Análisis de Suelos y de Espectroscopia Mössbauer. Facultad de Ciencias Físicas. Universidad Nacional Mayor de San Marcos, Apartado 14-0149, Lima 14.Perú. *Corresponding author: e-mail: malucelo@hotmail.com Keywords: Meteorite, Ar-51, X-ray diffractometry, transmission Mössbauer spectroscopy. Topic: T10- Physical Metallurgy and Materials Science Mossbauer spectroscopy has proven to be a useful tool to study meteorite samples [1, 2], especially for this meteorite designated Ar-51 because it revealed rather different mineralogical phases. Ar-51 belongs to a collection of the Museum of Natural History of the Universidad Nacional Mayor de San Marcos, Lima, Peru; it was collected in the Region of Arequipa, about 900 km south of Lima; the exact site is unknown. The sample has a mass of about 1 kg; its surface is rough with reddish incrustations, probably caused by weathering. A piece of the sample was removed by cutting in order to proceed with the study of its phase composition using X-ray diffractometry (XRD) and 57Fe transmission Mössbauer spectroscopy (TMS); energy dispersive X-ray fluorescence (EDXRF) was used to study its elemental composition. In Figure 1 we can observe the results of the analysis of the content of structural phases by XRD; the following phases were found; albite (Al)-(Na,Al,Si3O8), augite (Au)-(Ca,Mg,Fe)2(Si,Al)2O6, pyroxene (Py), and clinopyroxene (Cly) (XY(Si,Al)2O6); the following metallic phase corresponding to the iron oxide magnetite (Mg)-(Fe3+)A (Fe22.5+)BO4 was also found. There is abundant albite and overlapping of the peaks belonging to the main phases Au, Al and Py; at 2= 35.75º we can observe the overlapping of the reflection peaks from Mg, Au y Py. The TMS spectra were taken at room temperature and high velocity. See Figure 2, where the following subspectra are observed: two paramagnetic doublets due to sites occupied by Fe2+, in the phases Py and Au; one doublet occupied by Fe3+ in another paramagnetic site assigned to Cly; and three magnetic sextets assigned to an oxidized magnetite (Fe3‐X O4): one of them has been assigned to the A‐tetrahedral sites occupied by Fe3+ with Bhf = 49.2 T, and the other two sextets to the B-octahedral sites with Bhf = 48.7 T and Bhf = 46.4 T, due to possible different directions of the hyperfine magnetic with respect to the principal axis of the crystalline electric field gradient. Figure 1. Diffractogram of the Ar-51 meteorite sample showing: albite (Al), pyroxene (Py), augite (Au), magnetite (Mg) and clinopyroxene (Cly) Figure 2. Mössbauer spectrum of the Ar-51 meteorite sample taken at room temperature (RT) Al – Albite Py – Pyroxene Au – Augite Mg – Magnetite Cly – Clinopyroxene 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 References 1800 1600 1400 1200 1000 800 600 400 200 0 AR-51 (Arequipa) Al Au Cly Py Au Mg Au Au Al Mg Py Au Py Au Py Py Al Cly Al Al Au Au Au Au Py Py Py Py Py Py Py Py Py Py Py Al Al Al Al Al Al Al Al Al Al Al Al Al Mg Mg Cly Cly Al 2 theta Intensity AR-51 -10 -5 0 5 1 0 1 .00 0 .99 Relative transmission (%) 0 .98 0 .97 0 .96 0 .95 Velocity (m m /s) [1] María L. Cerón Loayza et al. 2014. Hyperfine Interactions Volume 224, Combined 1-3, 143-152, DOI: 10.1007/s10751- 013-0866-x [2] María L. Cerón Loayza et al. 2011. Hyperfine Interactions Volume 203, Numbers 1-3, 17-23, DOI: 10.1007/s10751- 011-0365-x [3] Mössbauer Spectroscopy.Tutorial Book. Chapter 3.Application of Mössbauer Spectroscopyin Earth Sciences.Robert E. Vandenberghe and Eddy De Grave.
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    T10 MÖSSBAUER SPECTROSCOPYSTUDY OF TWO CHONDRITE TYPE METEORITES María L. Cerón Loayza*, 112 Jorge A Bravo Cabrejos Laboratorio de Análisis de Suelos, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima 14, Perú. *Corresponding author: e-mail: malucelo@hotmail.com Keywords: chondrite meteorites, X-ray diffractometry, Mössbauer spectroscopy Topic: T10- Physical Metallurgy and Materials Science This work reports the results of the study of two chondrite meteorites. One of them impacted in an inhabited zone on 15 September 2007 in the neighborhood of the town of Carancas, Puno Region, about 1,300 km south of Lima, and is classified as type IV chondrite. The second one impacted on 16 October 1975 in the state of Zacatecas, Mexico, and is classified as an ordinary LL5 chondrite; it has been denominated Tuxtuac. The physical characteristics of chondrite meteorites deserve special study in order to understand the formation and origin of the materials of extraterriastral origin that have been deposited in the Earth. There are previous studies of these two chondrite meteorites, such as the type IV from Carancas, which was recovered in situ [1,2] and the type LL5 Tuxtuac, whose magnetic properties have been studied in detail [3-5]. Hence, Mössbauer spectroscopy is a powerful tool to compare these two Chondrites found in the southern hemisphere of our planet and obtains more detailed information about metallic phases in this sample, using the 14.413 keV gamma ray nuclear transition in 57Fe. A conventional spectrometer was used with a sinusoidal velocity modulation signal and 1024 channels. The Mössbauer spectrum at room temperature (RT) of the sample was collected at the Laboratory of Archaeometry, Facultad de Ciencias Físicas, UNMSM. A 57Co source in a Rh matrix was used to collect the spectra, which were analyzed using the Normos program by Brand in its crystalline sites version and distribution of sites (Normos Site) [5]. The results show the presence of silicates such as olivine, pyroxenes and other sites of Fe+3; metallic phases such as taenite and opaque phases such as troilite. In figure 1(a) we can see the spectrum from Tuxtuac and in 1(b) we can see the spectrum taken from the magnetic portion extracted from this sample using a magnet; this information helped to define one of the metallic phases. (a) (b) Figure1. Mossbauer spectra of the chondrite meteorite Tuxtuac (a) the sample as found, and (b) only the magnetic fraction. Both spectra were taken at a velocity of 12 mm/s. References [1]María L. Cerón Loayza et al. 2014. Hyperfine Interactions Volume 224, Combined 1-3, 143-152, DOI: 10.1007/s10751-
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    013-0866-x [2]María L.Cerón Loayza et al. 2011. Hyperfine Interactions Volume 203, Numbers 1-3, 17-23, DOI: 10.1007/s10751-011- 0365-x [3]Atsuko Yamanaka et al. Proc. NIPR. Symp. Antarct. Meteorites, 8, 305-323. 1995. [4] Takesi Nagata et. Al. National Institute of Polar Research. 364-381. 1985. [4] A. L. Graham et.al. Meteoritics 23, 321 -323 (1988). [5] Brand, R.A., NORMOS: Mössbauer Fitting Program, 1995. 113
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    T10 STRUCTURAL, MORPHOLOGICALAND MÖSSBAUER SPECTROSCOPY CHARACTERIZATION OF NANOSTRUCTURED TiFe0.5Ni0.5 Compound And Its Hydride 114 M. A. R. Martinez1, José André-Filho1, J. A. H. Coaquira1, L. L. Félix1, José Mestnik-Filho2 1Universidade de Brasília, Instituto de Física, Núcleo de Física Aplicada, Brasília, DF, CEP 70910-900. 2Instituto de Pesquisas energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, CEP 05508-000 *Corresponding author: e-mail: fisicorodriguez@gmail.com Keywords: intermetallic, ball milling, hydrogenation Topic: T10- Physical Metallurgy and Materials Science One way to improve the storage capacity of solid state matrices is to use intermetallic nanostructured materials. A high storage capacity is obtained with TiFe alloys (~1.9 wt%). The substitution of Fe by Ni can improve the activation of grains surface and reduce the equilibrium pressure of the hydride [1]. It is known that the presence of carbon clusters can improve the hydrogen absorption capacity of Ti-Fe-Ni nanostructured compounds [2]. In this work, we present the study of the structural, morphological and hyperfine properties of carbon-modified TiFe1-xNix (x=0.5) nanostructures and their hydrides. Bulk intermetallic matrices are prepared by a commercial arc-voltaic furnace and the carbon-modified nanostructured compounds are synthetized by using a ball milling equipment, under argon atmosphere. Hydrides compounds are obtained using the Sievert method with a high-purity hydrogen gas. The structural properties and crystallite sizes are determined by X-ray diffraction (XRD) technique. The hyperfine properties are characterized by Mössbauer spectroscopy and the morphological properties are studied by using Scanning electron microscopy (SEM). XRD data analysis indicates the formation of an intermetallic compound of single phase. Although, the milling process does not modify the crystalline phase, it drives to the broadening of the Bragg reflection peaks. That line broadening has been assigned to the crystallite size reduction and to the presence of residual strain. After the hydrogenation, it has been observed the formation of only the ∝ phase (hydrogen poor phase) for the unmilled sample. However, the coexistence of the ∝ and γ phases (hydrogen rich phase) has been determined for carbon-modified nanostructured sample. The analysis of the Mössbauer spectrum of the intermetallic TiFe0.5Ni0.5 alloy (bulk) obtained at room temperature (Fig.1a) is well-fitted with a singled whose isomer shift (IS) value is consistent with that one of TiFe alloy (within the uncertainty range). The Mössbauer spectra of the hydrogenated sample (Fig. 1b) were well-fitted with a singlet and a doublet which were associated with the  and β (a hydride phase) phases, respectively. No remarkable change was observed for the IS in the  phase, however, in the β phase, the IS showed a relative increase of +0.20 mm/s with respect to the alloy without hydrogen. This increase has been associated with a decrease in the “s” electron density at the Fe nucleus. On the other hand, the distortions produced by the hydrogen atoms provoke a crystalline phase transition from ∝ to β phase and it is manifested by the appearance of a nonzero quadrupole splitting (QS~0.21 mm/s). The Mössbauer spectra of the milled sample with carbon (Fig.1c) is well-resolved with a singlet and a sextet which correspond to the ∝ phase and metallic iron (likely arising from the milling vial set), respectively. For the carbon-milled sample (Fig. 1d), besides the singled and sextet, it has been determined the presence of a doublet with an IS of +0.36 mm/s [3] and a QS of 0.74 mm/s which was related to the γ phase in consistency with the XRD data. It suggests that the formation of the γ phase can be assigned to the presence of carbon which acts as a catalyst. Figure 1. Room temperature Mossbauer spectra of TiFe0.5Ni0.5 samples: bulk (a) and milled (c) and their hydrides (b) and (d), respectively.
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    References [1] Y.Liu, H. Pan, M. Gao, Q. Wang, J. Mater. Chem. 21, 4743 (2011) [2] E. M. B. Heller, A. M. Vredenberg, D. O. Boerma, Appl. Surf. Sci. 253, 771-777 (2006) [3] L J Swartzendrubert, L H Bennettt and R E Watson J. Phys. F: Metal Phys., 6, 12 (1976) 115
  • 120.
    T10 SYNTHESIS OFA 300 TYPE STAINLESS STEEL BY MECHANICAL ALLOYING David Mena1, Jeferson 2000 1600 1200 800 116 Piamba Jimenez2, Modesto Fajardo3, German Antonio Pérez Alcázar2, Héctor Sánchez Shepa1 1Escuela de Ingeniería de Materiales Universidad del Valle. 2Departamento de Física Universidad del Valle. 3Departamento de Física Universidad del Cauca. *Corresponding author e-mail: hector.sanchez@correounivalle.edu.co key words: mechanical alloying, high energy ball mills, X ray diffraction, Mössbauer Spectrometry, stainless steel. Topic: T10- Physical Metallurgy and Materials Science The stainless steel type 300 is a set of austenitic steels readily for undergoing plastic deformation and they are used as containers because of their mechanical and corrosion resistance. We produced a composition: Cr 18%, Ni 9%, Mn 2 and the balance Fe, from technical pure powders utilizing a high energy ball mill.PM 400 Retsch®. A 1:20 mass powders to mass balls ratio was used and angular velocity of 300 rpm of the sun wheel. The milling was carried out under a vacuum of the order of 10-1mbars and The milling times were: 1, 4, 8, 12,15 18 hours. As the times elapsed, approximately 3gr of powder were taking off the anvils and an amount of balls just to maintain the stipulated mass powders to mass balls ratio. The evolution of the alloy was monitored by Mössbauer spectrometry and X ray diffraction. Each technique was fitted by the Rietveld method and Mosfit repectively, besides images from SEM were analized to assure the alloy was completed. 1,00 0,98 0,96 0,94 Hecho por Juan David Mena Guzman Hecho por Juan David Mena Guzman Experimental Teorico Singlete Distribucion Ajuste de los espectros mossbauer -9 -6 -3 0 3 6 9 Today's date is 03/03/2014 The Document name is: "UNTITLED.opj, A18HMENA#p" relative transmission V [mm/s] J.D.Mena 18 Horas 20 40 60 80 100 400 Intensidad (u.a) 2 Experimental Teorico Linea Base Diferencia FeNi NiMnCr Juan David Mena Guzman 18 Horas Hecho por Juan David Mena Guzman Mössbauer Spectrum, X ray diffraction and SEM image showing the alloy is consolidated. M.M.Rico, J.Sort, D.Baro, S.Suriñach, J.M.Greneche y G.A.PerezAlcazar–Análisis estructural de la serie Fe60Mn10Al30- XBX (2 ≤ X ≤ 10) preparada por aleamiento mecánico–Departamentos de Física de la universidad del Valle (Colombia), universidad de Barcelona (España) y universidad de Maine (Francia) - 2001.
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    Mössbauer Effect Referenceand Data Journal August 2014 • Volume 37 • Number 6 Article and number are included under the authorization of Mössbauer Effect Reference and Data Journal. 117
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    118 Mössbauer Effect Reference and Data Journal Editors Tao Zhang Director Frank Berry, John Stevens Honorary Directors Junhu Wang Secretary General Changzi Jin, Xin Liu Research Associates Duorong (Lucy) Liu, Ya Ma Editorial Assistants Associate Editors AUSTRALIA P. de Souza BELGIUM Y. Garcia COLOMBIA C. A. Barrero JAPAN K. Nomura Y. Yoshida KOREA C. S. Kim RUSSIA I. S. Lyubutin Yu. D. Perfiliev V. G. Semenov USA E. E. Alp MEDC International Advisory Board AUSTRALIA S. J. Campbell – University of New South Wales AUSTRIA M. Reissner – Technische Universität Wien BELGIUM Y. Garcia –Université Catholique de Louvain BULGARIA I. Mitov – Institute of Catalysis, Bulgarian Academy of Sciences BRAZIL J. D. Fabris – Universidade Federal de Minas Gerais CHINA Y. F. Hsia – Nanjing University J. Y. Shen – Nanjing University FRANCE J.-C. Jumas – University of Montpellier II - Regional Mössbauer Platform J. -M. Grenèche - Université de Maine R. Rüffer – European Synchrotron Radiation Facility GERMANY F. E. Wagner – Technische Universität München H. Engelmann – Englemann Scientific Technologies HUNGARY E. Kuzmann – Eötvös Loránd University ITALY M. Carbucicchio – Università degli Studi di Parma JAPAN M. Takahashi – Toho University KOREA C. S. Kim – Kookmin University OMAN A. A. Yousif – Sultan Qaboos University RUSSIA S. M. Irkaev – Institute for Analytical Instrumentation, Russian Academy of Sciences M. Y. Silin – RITVERC GmbH SPAIN J. F. Marco – Instituto de Química-Física “Rocasolano” SWEDEN L. Häggström – Uppsala Universitet USA C. Wynter – Nassau Community College T. Kent – SEE. Co. The Mössbauer Effect Reference and Data Journal (MERDJ) is published ten times a year (each month excluding January and February) plus an Index Issue at the end of December by the Mössbauer Effect Data Center. Subscriptions: The annual subscription rate for Volume 37 (2014) is US$1,500.00 ($1,200.00 without the Index Issue). Subscription inquiries and address changes should be addressed to the General Manager at the address below. Mössbauer Effect Data Center Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road, Dalian 116023, China Tel: +86 411 8437 9159 Fax: +86 411 8468 5940 Email: medc@dicp.ac.cn Web: www.medc.dicp.ac.cn ISSN 0163-9587 On the cover: This issue, our front cover is graced by the memorial pictures of Professor José Domingos Fabris for continuously celebrating the 25th anniversary of the world largest regional Mössbauer community. See Editor’s Comments and the contents in the enclosed Mössbauer Spectroscopy Newsletter th
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    Mössbauer Effect Referenceand Data Journal 119 August 2014 • Volume 37 • Number 6 Contents Contents ........................................................................................................................................................................... 129 Reference Listing............................................................................................................................................................. 131 Data Listing ..................................................................................................................................................................... 136 Subject Index ................................................................................................................................................................... 139 Mössbauer Newsletter ................................................................................................................................................... 141 Editor’s Comments The Latin America Community of Mössbauer spectroscopy was founded in 1982, and till 2013 it had been successfully operated 25 years. It is the largest regional Mössbauer community in the world and biennially organizes the local conference of LACAME (Latin American Conference on the Applications of Mössbauer Effect). It has been having a very close relationship with the MEDC for a long time, and now this close relationship was well maintained after the MEDC was relocated in Dalian. In 2010 and 2012, I and Professor Tao Zhang, the current director of MEDC, were invited to attend the LACAME conferences held in Lima and Medellin, respectively. Lima’s trip was very memorable for me as it was the longest flight (about 30 hours’ flight) in my life. For celebrating the 25th anniversary of the Latin America Community of Mössbauer spectroscopy, initiated by Professor Roberto Carlos Mercader from Argentina, I accepted Tao Zhang’s suggestion and started to organize our special issues of the MEDC data journal, MERDJ. I was fortunate enough that five of the most active Mössbauer scientists could kindly accept my invitation and submit their excellent contributions to the special issues. So it’s an extreme pleasure that our readers can enjoy the article from the founder of LACAME as well as the former vice chair of IBAME, Professor Elisa Baggio Saitovitch from Brazil. Last issue, we had officially kicked off the special issues for celebrating the Latin American Community of Mössbauer spectroscopy by sharing the celebration articles contributed by the representatives of seven Latin American countries, Professors’ Elisa Baggio Saitovitch and Roberto Carlos Mercader. This issue, we continue the celebration by publishing Professor José Domingos Fabris’s contribution. The details, please read the enclosed Mössbauer spectroscopy newsletter. Junhu Wang Secretary General and Editor
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    is pleased tooffer these publications and services to the international Mössbauer community... The Journal reports as thoroughly as possible all published information on Mössbauer spectroscopy. An annual subscription includes ten issues plus an index issue. Each issue includes a Reference Listing, a Data Listing, an Abbreviation Listing, an Isotope Index, a Subject Index, and the Mössbauer Spectroscopy Newsletter. Mössbauer Web Sites ON THE WORLD WIDE WEB The Mössbauer Effect Data Center developed and administers two separate Web sites for the Mössbauer community (<www.mossbauer.org> and <www.medc.dicp.ac.cn> These sites provide Mössbauer researchers with pertinent and timely information, free of charge. Included on the sites are general information pertinent to the Mössbauer community, news items, regional lab information, position postings, information on upcoming conferences, the most recent Mössbauer Spectroscopy Newsletter, IBAME information, an E-Mail and Fax Directory of Mössbauer Authors, links to Mössbauer instrument and source suppliers, and further information regarding the Center's products and services. Access to the MEDC Web-Access Database is also provided through the MEDC site. Researchers may now access and search the MEDC database from their computers via the MEDC Web site. The MEDC Database contains both a Reference and a Data file, and includes search, sort, and print functions. For further information about these and our many other publications and services for the Mössbauer community, please visit us at our Web site Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road, Dalian 116023, China Phone: +86-411-84379159 Fax: +86-411-84685940 Email: medc@dicp.ac.cn Web: www.medc.dicp.ac.cn www.mossbauer.org 120
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    121 Trends andchallenges of the Latin American Mössbauer community: a brief overview José Domingos Fabris Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), PRPPG, Campus JK, 39100-00 Diamantina, Minas Gerais, Brazil, and Department of Chemistry - ICEx, Federal University of Minas Gerais (UFMG), 31270- 901 Belo Horizonte, Minas Gerais, Brazil. Email: jdfabris@ufmg.br Abstract T he m a p of t h e nu m be r of Mö ssb a ue r spectroscopy publications worldwide has changed in different regimes of evolution over the three last decades. The main tendencies were reportedly systematized by broadly grouping them according to countries of the institutional affiliations of their authors. In Latin America, four countries - Argentina, Brazil, Colombia and Mexico – were responsible for ~3.7% of the global articles published be twee n 1958 a nd 2009 a nd ~93% of t he articles on Mössbauer spectroscopy of all Latin American authors between 1958 and 2009. For these four countries, certainly as an image of a much broader regional trend, the research activity has been constantly increasing since the 1980s. This trend emphasizes the role of the Latin American Conference on the Applications of the Mössbauer Effect in this regional performance over the last twenty five years and of its strategic importance in broadening the Mössbauer spectroscopy culture for future generations of researchers. It boosts connections to their scientific works and opens new opportunities to address developments following new technological demands, particularly those with more regional appeals. The cited scientific references in this text come essentially from a personal selection to merely sustain the arguments to stimulate multilateral scientific integrations, in part based on my self- August 2014 experience, but they do not intend to represent in any completeness the ample scientific world involving Mössbauer spectroscopy in Latin America. José Domingos Fabris: Doctor in Science – Chemistry (1977) at the Federal University of Minas Gerais (UFMG), Brazil; Post-Doctoral at the Centre d'Études Nucléaires de Grenoble (1978), France, and at the Department of Crystallography, Birkbeck College, London Uni ve rsi t y (1991), E ngl a nd; L e c t ure r of Che m i st ry (1971 – 1986) a t t he Fe de ra l University of Viçosa, Brazil; Senior Researcher (1986 – 1997) at the Brazilian Agriculture Research Organization - EMBRA PA; Full Professor of Chemistry (UFMG, 1997 - 2010; currently, retired); CAPES (Brazil)/Fulbright (USA) Senior Visiti ng R e searche r (March – June 2006) at the University of Illinois at Urbana-Champaign, USA; Visiting Professor (PVNS/CAPES program, from 2010 to present) at the Federal University of the Jequitinhonha and Mucuri Valleys, Brazil. A list of scientific publications may be found on the curriculum vitae (in Portuguese) at the web address http:// lattes.cnpq.br/8091857216878149.
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    122 1. Introduction Born from the elegant physical arguments used to explain experimental results of the resonant absorption of gamma radiation involving recoilless atomic nuclei, the Mössbauer effect was formally described and first reported by its discoverer, Rudolf Ludwig Mö ssb a u e r, i n 1 9 5 8 [ 1 , 2 ] . T h e r e su l t a n t Mössbauer spectroscopy was first used for studies of problems on the physics and chemistry of solids and progressively expanded to other topics on a wider range of the more recent scientific and technological fields. During the fifty years from 1958 to 2009, more than 70,000 Mössbauer spectroscopy articles were published [3]. If calculated per year, the maximum number of annual publications was reached during the 1990s and declined globally since (Figure 1). But [4]. Figure 1. Mössbauer spectroscopy publications per year (1958 - 2009); data obtained from refs. [3] and the profile of the publications is distinguishable according to the group of countries. The first group of histograms in Figure 2, corresponding to data for China, France, Germany and Japan, represents countries that responded for about 29% of all Mössbauer spectroscopy articles from 1958 to 2009, and for which the related research activity followed the general increasing trend from the 1980s to the 1990s, followed by a decrease in the 2000s. The second group of histograms, for Canada, England, India, Russia and the USA (~33% of all articles between 1958 and 2009), represents countries in which activity has been decreasing for the last two decades relative to that of the 1980s. Finally, for the group of countries encompassing the Czech Republic, Oman and Pakistan (~0.3% of all articles between 1958 and 2009), along with the four Latin American countries ― Argentina, Brazil, Colombia and Mexico – who are responsible for ~3.7% of the global articles between 1958 and 2009 and ~93% of all the articles on Mössbauer spectroscopy from Latin American authors between 1958 and 2009. For these four Latin American countries, the research activity has been constantly increasing since the 1980s. According to the data of [3], the number of Mössbauer spectroscopy publications by all Latin American authors between 1958 and 2009 represented about 4% of all the corresponding articles published worldwide. 2. What might those data mean? The identification of the main reasons governing these trends is not an easy or fully reliable task. The inspection of histograms in ref. [4] reveals that some Mössbauer topics (e.g., synchrotron Mössbauer, superconductivity, magnetism, exotic isotopes, spin crossover effects w ith phas e trans itions ) have been historically dominant and reached a maximum number of global publications during the 1990s
  • 127.
    Figure 2. Thedynamics of the number of publications on Mössbauer spectroscopy over three decades (1980s, 1990s and 2000), as represented by the three sequential bars, per geographic region [4]. The first group of charts (brown) represents areas in which activity followed the general trend of increase from the 1980s to 1990s, and then a decrease in the 2000s. The second group of charts (red) represents areas in which activity has been decreasing for three decades. The final group of charts (green) represents areas in which activity has been constantly increasing since the 1980s. (in the case of nanoparticles, during the 2000s), but decreased slightly since then. Moreover, a comparison of the data for 2008 with that of 2000 indicates that research activities worldwide related to oxides, metals, alloys and minerals have evolved [5] (Figure 4). The increase in scientific topics corresponds to what can be broadly interpreted as being the preferred area of Mössbauer research in Latin American laboratories (Figure 5): oxides and corrosion, alloys and, remarkably, mineralogy. The main research activities correlated with the number of laboratories [6] (Figure 5) appear in the following order: mineralogy > alloys > corrosion ≈ nanotechnology. However, Latin American Mössbauer researchers have also been done significant work on magnetism, medical technologies, environmental problems, archaeometry and theoretical/fundamental physics. 123 An analytical focus on the scientific
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    124 competence ofindividual researchers and on the physical facilities found in many Latin American Mössbauer laboratories evidences their capability to solve problems related to the assessment in deeper knowledge of the natural resources, of the cultural meaning of materials and their historical artifacts, the preservation or remediation of polluted areas in their natural environment and the rational use of the mineral richness for technological purposes in the countries of the region. This understanding has been, in part, stimulating collective efforts of the regional Mössbauer community to become integrated by sharing their laboratory facilities, opening opportunities for the exchange of students and researchers among countries, and by promoting regional scientific meetings. The integration has culminated in the advent of the biennial Latin American Conference on the Applications of the Mössbauer Effect (LACAME) twenty-five years ago and has been
  • 129.
    Figure 3. Distributionof publications on Mössbauer spectroscopy per Latin American country between 125 1958 and 2009 (based on data from ref. [3]) Figure 4. Number of publications per selected topic in 2000 and 2008 (based on data from ref. [4]).
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    Figure 5. Somegeneral Mössbauer topics being dealt with by Latin American Mössbauer groups. Frequency values on the ordinate axis were deductively drawn from refs. [5] and [6]. rendering significant practical results. 126 A few and sparsely chosen scientific studies of our groups at the UFMG and at the UFVJM that have been done in collaborations with colleagues in Brazil and in neighboring countries (mainly in Argentina, Chile, Colombia and Peru) may be broadly grouped according to some scientific or technological interests. In Brazil, collaborators have been more often of the Brazilian Center of Physical Research (CBPF), in Rio de Janeiro; the Center for the Development of the Nuclear Technology (CDTN), in Belo Horizonte, Minas Gerais; the State University of Maringá (UEM), in Paraná; the Federal University of Espírito Santo (UFES), the Federal University of Ouro Preto (UFOP), in Minas Gerais, and the Federal University of Pi a uí (UFPI). In ot he r L a t i n Am e ri c a n countries, mainly of the National University of La Plata (UNLP), Argentina; the University of Santiago (USACH), Chile; the Pedagogical and Technological University of Colombia (UPTC), in Tunja, Colombia and the University of San Marcos (UNMSM), Peru. 3. Specific topics 3.1. Mineralogy Taking into account only selected cases related to the various geological systems in the Latin America, tropical and sub-tropical soils [7, 8] and sediments [9] in Brazil and volcanic geomaterials from Chile [10] are commonly rich in iron-bearing minerals, some of which are magnetic. Understanding their chemical, physical and mineralogical properties has also been a fundamental concern in the perspective of using them for technological purposes, such as adsorbents or catalysts for environmental remediation or energy production. Systematic collaborative studies involving researchers at the UFMG, USACH and UFVJM have been devoted to the mineralogy of magnetic iron oxides in volcanic soils from Chile in advanced oxidation processes (AOP; specifically, the Fenton reaction) for environmental remediation (e.g., [11, 12]) and the water gas shift gas reaction [13] to produce hydrogen from carbon monoxide and water. Moreover, other minerals, more specifically zeolites and imogolite from those volcanic geomaterials from Chile, were found to form interesting magnetic composites with magnetite, which has a high adsorptive ability, to remove anions from contaminated water in environmental remediation of areas affected by mining activities [14-16]. In antiquity, human groups also used minerals for rupestrian paintings and the production of (now) archaeological ceramics.
  • 131.
    127 Long-term jointstudies by researchers and undergraduate and graduate students at the CBPF, CDTN, UFMG, UFPI and UFVJM have successfully identified iron oxides of archaeological ceramics [17] and pigments of rupestrian paintings [18, 19] in Brazil. Pigment materials from rupestrian paintings c a nnot a rbi t ra ri l y be obt a i ned by di re c t l y removing them from rock walls in protected archaeological sites or from fragments of archaeological pieces. Mainly for this reason, Mössbauer non-destructive measurements must be performed in s itu . The U FP I has recently acquired a backscattering MIMOS II Mössbauer setup [20] to be specially used for archaeological studies. 3.2. Pedology: iron in organic soils Iron has been considered a pedogenic marker to help trace pedogenetic mechanisms in organic soils. For the first time, 57Fe Mössbauer measurements in samples of peat mires from two sites of the upper Jequitinhonha Valley, Brazil, were recently performed by researchers from the UEM, UFVJM and UNLP [21, 22]. 3.3. Iron ore mines and industrial beneficiation of kaolin Mössbauer spectroscopy has also been the key tool in assessing the iron mineralogy of geomaterials from nickel [23] and coal [24, 25] mines in Colombia, and manganese, in Brazil [26], and in tracking chemical changes induced by industrial processing of kaolin from mines in Brazil [27-29]. 3.4. Synthetic iron oxides P u r e i r o n o x i d e s o r i r o n o x i d e s isomorphically-doped with foreign cations for use as heterogeneous catalysts for advanced oxidation [30] have been synthesized at the UFMG. They are to be used to clean natural water bodies contaminated with or ganic pollutants and for photocatalysis, to promote the molecular splitting of water and produce gaseous molecular hydrogen [31]. Nanosized magnetic iron oxides forming ferrofluids have been assayed at the CDTN, UFES, UFMG, UFOP and UFVJM in attempts to assess their structural (crystallographic, magnetic, and hyperfine) properties and obtain experimental data regarding the potentiality of their use in advanced technologies for medical diagnosis and therapy (hyperthermy and magnetically-o ri e nt e d d ru g de l i v e ry ) i n o nc o l o g y [ 32 ] (reviews also covering aspects of those studies are in refs [33-35]). 4. Concluding remarks The Mössbauer communi ty in Lat in American is experiencing an increase in scientific activities, considering the number of publications; the number of active Mössbauer laboratories, such as the new setup at USACH, Chile, and their capability is also expanding, although laboratories are still more concentrated in Argentina, Brazil and Colombia. National meetings (for instance, the biennial Jacques Danon Meeting on Mössbauer spectroscopy in Brazil) and the regional Latin American Conference on the Applications of the Mössbauer (LACAME) have been boosting the exchange of students and researchers in and among the countries of Latin America and the Caribbean, geographically covering a significant proportion of the American continent. LACAME has been playing a master role by creating the proper forum to integrate joint actions of more individual scientific teams for the past twenty-five years. Although many similar and more extensive examples than the multilateral collaborative works cited above can be found that also involve Brazilian and other researchers of institutions in Latin American countries, quite certainly, most of these integrating initiatives have emerged from the scientific atmosphere at the LACAME meetings. It must also be remarked that, despite the fact that more sophisticated physical facilities a nd o t he r r e sour c e s, i nc l u di n g e xp e rt i se , can be optimized and shared, particularly by geographically closer laboratories, there are a few immediate, unavoidable challenges in the horizon for the future of Mössbauer spectroscopy in Latin America: i. Suppl y, handl ing a nd t ransport of Mössbauer radioactive sources. ii. Maintain and improve academic and scientific exchange of students dealing with Mössbauer spectroscopy throughout the Latin American countries. The national supporting agencies may act by more intensely “catalyzing” those actions. iii. National and regional Mössbauer meetings might be more highly focused on major “hot topics”, which would be chosen for each meeting, while keeping them unrestrainedly free and open for all scientific contributions. iv. Would a multinational laboratory to provide the most sophisticated and usually expensive facilities (very low temperature, magnetic field, special Mössbauer sources…)
  • 132.
    128 be areasonable alternative to complement the current individual laboratory facilities in Latin America; v. Mössba ue r sync hrot ron. Can t he Brazilian National Laboratory of Synchrotron Light provide the radiation beam-line and host the corresponding Mössbauer setup? At least some of these few points may become recommended items for fruitful discussion by the Latin American Mössbauer community and at the LACAME forum. 5. Acknowledgments The author is indebted to CAPES (Brazil) for granting his Visiting Professorship at the UFVJM under the PVNS program and t o the FAPEMIG and CNPq (currently, grant # 305755-2013-7; Brazil) for having supported many of the Mössbauer laboratory activities at the UFMG and UFVJM; also to my colleagues David Lee Nelson, Enver Murad and Luis Carlos Duarte Cavalcante for their helpful comments on the manuscript. The scientific interest and research activities of this author on the physics of iron-bearing minerals were also built up and markedly strengthened all along the more than two decades of scientific cooperation, from the beginning of the 1980s, with Professor John Michael David Coey, Department of Physics, Dublin University, Ireland. 6. References [1] R. L. Mössbauer: Kernresonanzfluoreszenz von Gammastrahlung in Ir-191, Zeitschrift für Physik 1958, 151(2), 124. [2] R. L. Mössbauer: Kernresonanzabsorption von Gammastrahlung in Ir. Zeitschrift für Naturforschung. Part A-Astrophysik Physik und Physikalische Chemie 1959, 14(3), 211. [3] The Mössbauer Effect Data Center: Total Number of Publications per Country 1958-2009 , Mössbauer Effect Reference and Data Journal 2009, 32(5), 72. [4] Stevens, J. G.: The Future of the Mössbauer Effect Data Center Conference. Talk at the opening ceremony of MEDC relocated in Dalian, China, in July 2010. [5] The Mössbauer Effect Data Center: The Latin American Mössbauer Community, Mössbauer Effect Reference and Data Journal 2004, 27(7), 183. [6] The Mössbauer Ef fect Data Center: Mössbauer Spectroscopy in Latin America, Mössbauer Spectroscopy Newsletter October 2008. [7] J. D. Fabris, J. M. D. Coey, W. N. Mussel: Magnetic Soils from Mafic Lithodomains in Brazil, Hyperfine Interactions 1998, 113, 249. [8] J. H. M. Viana, P. R. C. C Couceiro, J. D. Fabris, E. E. Fernandes Filho, C. E. G. R. Schaefer, H. R. Rechenberg, W. A. P. Abrahão, E. C. Mantovani: Occurrence of Magnetite and its Transformation to Hematite in the Sand Fraction of a Brazilian Oxisol, Australian Journal of Soil Research 2006, 44(1), 71. [9] G. T. Aragon, F. L. Silva, D. A. Bustamante, R. B. Scorzelli, J. D. Fabris: Chemical Dynamics of Fe Compounds in Brazillan Mangrove Sediments Studied by Mössbauer Spectroscopy, In: M. F. T hom a s, J. M. Wi l l i a m s, T. C. Gi bb. (Orgs.). Hyperfine Interactions (C) 2002, 1ed. Dordrecht, Kluwer Academic Publishers, 5, 387. [10] A. C. Silva, M. Escudey, J. E. Förster, C. Pizarro, J. D. Ardisson, U. M. Barral, M. C. Pereira, J. D. Fabris: Iron-bearing Minerals in Ashes Emanated from Osorno Volcano, in Chile, Hyperfine Interactions 2014, 224, 153. [11] V. Manzo, C. Pizarro, M. A. Rubio, L. C. D. Cavalcante,V. K. Garg, J. D. Fabris: Preparative Treatment With NaOH to Selectively Concentrate Iron Oxides of a Chilean Volcanic Soil Material to Produce Effective Heterogeneous Fenton Catalyst, Hyperfine Interactions 2011, 203, 59. [12] S. Aravena, C. Pizarro, M. A. Rubio, L. C. D. Cavalcante, V. K. Garg, M. C. Pereira, J. D. Fabris, J.D.: Magnetic Minerals from Volcanic Ultisols as Heterogeneous Fenton Catalysts, Hyperfine Interactions 2010, 195, 35. [13] C. Pizarro, M. Escudey, S. A. Moya, J. D. Fabris: Iron Oxides From Volcanic Soils as Potential Catalysts in The Water Gas Shift Reaction, In: M. Garcia, J. F. Marco, F. Plazaola (Orgs.), Industrial Applications of the Mössbauer Effect - International Symposium on the Industrial Applications of the Mössbauer Effect. American Institute of Physics - AIP Conference Proceedings 2005, 765, 56. [14] M. Gutierrez, M. Escudey, J. Escrig, J. C. Denardin, D. Altbir, J. D. Fabris, L. C. D. Cavalcante, M. T. García-Gonzalez: Preparation and Characterization of Magnetic Composites Based on a Natural Zeolite, Clays and Clay Minerals 2010, 58(5), 589–595. [15] N. Arancibia-Miranda, M. Escudey, C. Pizarro, J. C. Denardin, M. T. García-González, J. D. Fabris, L. Charlet: Preparation And Characterization Of A Single-Walled Aluminosilicate Nanotube- Iron Oxide Composite: Its Applications to Removal of Aqueous Arsenate, Materials Research Bulletin 2014, 51, 145. [16] L. C. A. Oliveira, R. V. R. A. Rios, K. Sapag, J. D. Fabris, R. M. Lago: Magnetic Particle Technology: A Simple Preparation of Magnetic Composites for the Adsorption of Contaminants in Water, Journal of Chemical Education 2004, 81(2), 248. [17] D. L. Floresta, J. D. Ardisson, M. Fagundes, J. D. Fabris, W. A. A. Macedo: Oxidation States of Iron As An Indicator of the Techniques Used to Burn Clays and Handcraft Archaeological Tupiguarani Ceramics By Ancient Human Groups In Minas
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    129 Gerais, Brazil,Hyperfine Interactions 2013, 224, 121. [18] L. C. D. Cavalcante, M. F. Luz, N. Guidon, J. D. Fabris, J. D. Ardisson: Ochres From Rituals of Prehistoric Human Funerals at The Toca do Enoque Site, Piauí, Brazil, Hyperfine Interactions 2011, 203, 39. [19] T. L. Alves, M. A. M. L. Brito, M. C. S. M. Lage, L. C. D. Cavalcante, J. D. Fabris: Pigmentos de Pinturas Rupestres Pré-Históricas do Sítio Letreiro do Quinto, Pedro II, Piauí, Brasil, Química Nova 2011, 34, 181. In Portuguese. [20] G. Klingelhöfer, G. B. Bernhardt, J. Foh, U. Bonnes, D. Rodionov, P. A. Souza, C. H. Schröder, R. Gellert, S. Kane, P. Gütlich, E. Kankeleit: The Miniaturized Mössbauer Spectrometer MIMOS II for Extraterrestrial and Outdoor Terrestrial Applications: A Status Report, Hyperfine Interactions 2002, 144/145, 371. [21] R. C. Me rc ade r, A. C. Si l va, M. L . Montes, F. R. Sives, A. Paesano Jr, J. D. Fabris: Chemical Fate of Iron in a Peatland Developing in the Southern Espinhaço Chain, Brazil, Hyperfine Interactions 2014, 226, 509. [22] A. Paesano Jr, A. C. Silva, F. F. Ivashita, C. F. Cerqueira, F. Sives, R. C. Mercader, J. D. Fabris: Chemical Reducing Pedoenvironment in A Peatland Influenced by Hematitic Phyllite Lithology in The Southern Espinhaço Chain, Brazil, Hyperfine Interactions 2014, 226, 585. [23] J. D. Fabris, C. M. Gonçalves, W. A. P. Serrano: Chemical and Mineralogical Analyses of a Weathering Mantle Developing on Peridotite of the Mining Area For Nickel in Cerro Matoso, Colombia, Hyperfine Interactions 1999, 122, 171. [24] W. A. Pacheco Serrano, D. Q. Lima, J. D. Fabris: Mössbauer Analysis of Coal Coke Samples from Sa m a c á , Boya c á , Col om bi a , Hy pe rf i ne Interactions 2013, 224, 271. [25] W. A. Pacheco Serrano, D. Q. Lima, J. D. Fabris: Mössbauer Analysis of Coal Coke Samples from Sa m a c á , Boya c á , Col om bi a , Hy pe rf i ne Interactions 2014, 224, 277. [26] C. K. Nascimento, M. C. Pereira, L. C. D. Cavalcante, A. M. Lana, E. Murad, J. P. Braga, J. D. Fabris: Hyperfine Structure of 57Fe in Minerals from a Manganese Ore Deposit, Hyperfine Interactions 2011, 203, 25. [27] P. G. Pinheiro, J. D. Fabris, W. N. Mussel, E. Murad, R. B. Scorzelli, V. K. Garg: Beneficiation of a Commercial Kaolin from Mar de Espanha, Minas, Gerais, Brazil: Chemistry and mineralogy, Journal of South American Earth Sciences 2005, 20(3), 267. [28] E. Murad, J. D. Fabris: Kaolin Mining and Beneficiation: the Role of Iron. Journal of Physics - Conference Series (Online) 2010, 217, 012066. [29] W. D. Mussel, E. Murad, P. S. R. Criscuolo, P. G. Pinheiro, J. D. Fabris: Variation of Mineralogy During the Beneficiation of Capim Kaolin from Pará, Brazil, Clay Minerals 2008, 43, 381. [30] D. Q. L. Oliveira, L. C. A. Oliveira, E. Murad, J. D. Fabris, A. C. Silva, L. M. Menezes: Niobian Iron Oxides as Heterogeneous Fenton Catalysts for Environmental Remediation, Hyperfine Interactions 2010, 195, 27. [31] M. C. Pereira, E. M. Garcia, A. C. Silva, E. Lorençon, J. D. Ardisson, E. Murad, J. D. Fabris, T. Matencio, T. Castro Ramalho, M. V. J. Rocha: Nanostructured -FeOOH: A Novel Photocatalyst for Water Splitting, Journal of Materials Chemistry 2011, 21, 10280. [32] P. Chagas, A. D. Silva, E. C. Passamani, J. D. Ardisson, L. C. A. O. Oliveira, J. D. Fabris, R. M. Paniago, D. S. Monteiro, M. C. Pereira: δ-FeOOH: A Superparamagnetic Material for Controlled Heat Release Under AC Magnetic Field. Journal of Nanoparticle Research 2013, 15, 1544. [33] A. L. Andrade, R. Z. Domingues, J. D. Fabris, A. M. Goes: Safety of Magnetic Iron Oxide- Coated Nanoparticles in Clinical Diagnostics And Therapy, In: H. A. Khan, I A. A. (Org.), 2012, Toxic Effects of Nanomaterials, 1ed Oak Park, Bentham Science Publishers 2012, 67. [34] R. V. Ferreira, J. D. Fabris, R. Z. Domingues: Magnetic Hyperthermia Studies in Magnetite Ferrofluids, In: D. M. Angrove (Org.), Magnetite: structure, properties and applications, New York, Nova Publishers 2011, 379. [35] A. L. Andrade, R. Z. Domingues, J. D. Fabris, A. M. Goes: Safety of Magnetic Iron Oxide- Coated Nanoparticles in Clinical Diagnostics and Therapy, In: H. A. Khan, I. A. Arif (Org.), Toxic E ffe c t s of Na nom a t e ri a l s 2012. 1 e d Oa k Pa rk, Bentham Science Publishers, 67.
  • 134.
    130 LACAME 2014,MEXICO Dear Mössbauer Community: The XIVth Latin American Conference on the Applications of the Mössbauer Effect – “LACAME 2014” will take place at the UAEM DECA in Toluca City in the State of Mexico, Mexico from November 10th to 14th, 2014. Toluca is a city located at more than 2600 m above sea level and at 70 km from Mexico City (around 1 hour by bus). The modern and constantly evolving industrialized Toluca City has been able to preserve the great cultural, artistic and natural heritage in its zone, which is characterized by the artistic genius of its people and the richness of its valleys. Its ancient history takes us to the Matlatzincas, who left their imprint in the archaeological zone of Calixtlahuaca. In the historical City Center one can still breathe the Colony period, when walking through the narrow alleys and big houses made of covered mud that take us to the Portals, where traditional candies and street concerts fill the air. There, the impressive architecture of the Cathedral, with its Roman reminiscences, the Merced Church and the Santa Veracruz Parish can be appreciated. Toluca's climate is the coolest of any large Mexican city due to its altitude, winter nights are cold and the temperature may drop below 0 °C (32 °F). Throughout the year, the temperature is rarely below −3 °C (27 °F) or above 27 °C (81 °F). LACAME (Latin American Conference on Applications of Mössbuer Effect) is a series of scientific events that take place every two years in some Latin American Country. This year, Mexico has been selected to host the 14th Conference on the applications of the Mössbuer Effect. This event not only stimulates the development of the Mössbuer spectroscopy but also offers a perfect frame for high level discussions. This Conference will offer both the Mexican and Latin American communities the opportunity of interacting with first class international researchers talking about different interesting topics. The Mössbuer spectroscopy is a suitable and powerful technique for very specific studies. Indeed, some of the great advantages featured by this technique are that in spite of its relatively low cost, it provides insightful results for advanced research studies and it can be applied in a variety of scientific and industrial fields.
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    131 Invited Speakers E. M. Baggio Saitovitch – CBPF Brazil Magnetism and superconductivity studies on doped BaFe2As2 single crystals seen by Mössbauer Spectroscopy. R.C. Mercader – UNLP Argentina Design of self and matrix supported systems of iron oxide nanoparticles for catalytic applications. C. A. Barrero - Universidad de Antioquia, Colombia Contributions of Mössbauer spectrometry t o t h e st u d y o f so me d i l u t e d ma g n e t i c semiconductor oxides: A critical review J. A. Jaen - Universidad de Panamá Structural, electrical and magnetic study on Li2Fe1-xNixSiO4 cathode material for lithium-ion batteries T h e O r g a n i z i n g C ommi t t e e o f LACAME-2014 is also planning some video conferences. The abstracts will be published in a meeting abstract book. Selected contributions will be considered for publication in a special issue of Hyperfine Interactions. Peer review with strict refereeing standards will be applied. Dates 20 June, 2014: Final announcement. 28 June, 2014: Deadline for abstracts. 10 A u gu st, 2014: N otification for the acceptance. 10 September, 2014: Deadline for earlier registration. 1 2 No v e m be r, 2 0 1 4 : De a d l i n e f o r a l l manuscripts. 10 - 14 November, 2014: LACAME 2014, México. Mex i can Gr oups with Mössbauer Laboratories I n st i t u t o Na c i o n a l d e I n v e st i g a c i o n e s Nucleares, ININ (National Institute of Nuclear Research). State of Mexico. Universidad Nacional Autónoma de México, UNAM (National Autonomous University of Mexico). Mexico City. Instituto Politécnico Nacional, IPN, (National Polytechnic Institute). Mexico City. Instituto Mexicano del Petroleo, IMP (Mexican Petroleum Institute). Mexico City Mössbauer Spectroscopy Topics devoted of Mexican groups are: (1) magnetic materials, 2) structural properties of iron based alloys 3) study of thin films of 57Fe by Mössbauer spectroscopy, DCEMS. However
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    132 most ofthem have been devoted to two main areas: corrosion and heterogeneous catalysis. In the last years these groups have been working to evaluate the corrosion produced in pipelines transporting crude and refined oil in the Mexican petroleum industry, which is one of the biggest in the world. These corrosion products have been obtained from sludge get from the pipeline cleaning with smart pigs or from a steel coupon exposed in an industrial environment. Concerning to heterogeneous catalysis; Mössbauer Spectroscopy has been used for applications in the oil refining and petrochemical industry. In relation to non-supported mixed oxide catalysts, one of these groups has came working on Fe-Zn-O and Fe-Zn-Cr-O mixed oxide materials applied to oxidative dehydrogenation of n-butane and 1-butene to butadiene. The Mössbauer spectroscopy technique has been used to elucidate the nature of active sites presents on bulk mixed oxides as well as the cooperative effect of different phas es present in the solids on its catalytic behavior. T h e i nc or p o ra t i o n of c h r om i u m i nt o z i n c ferrite catalyst greatly increases butadiene and CO 2 selectivity in n-butane oxidative dehydrogenation. The chromium incorporated into octahedral sites in the spinel structure seems to increase the basicity of the lattice oxygen. More basic oxygen seems to promote the acid-base type dissociation of the C-H bond during butane/butene activation to produce butadiene. In this same sense, in order to increase the exposed area of bulk mixed oxides, these materials were supported on silica and alumina. The Mössbauer spectroscopy technique has been used to show the effect of support on the electronic properties of active sites, presents on bulk mixed oxides, on its catalytic behavior. The IMP Mössbauer Spectroscopy group has applied with success this spectroscopy in the development of supported platinum-tin catalysts, which are widely used for the normal d e h y d r o g e n a t i o n o f l o w m o l e c u l a r we i g h t parafins (propane, butane and iso-pentane). Website: http://www.lacame2014.com Email: lacame2014@lacame2014 Call for IBAME awards IBAME (the International Board of the Applications of the Mössbauer Effect) rewards two merit based prizes: 1) the IBAME Young Scientist Award for researchers up to the age of 35, for high quality contribution to science based on research that involves application of the Mössbauer Effect and 2) the IBAME Science Award for a high quality contribution to science based on research that involves application of the Mössbauer Effect over an extended period of at least 20 years. Nominations should be submitted by two persons active in research related to applications of the Mössbauer Effect, at least one of whom is a current IBAME member. And they should be sent to the IBAME secretary Michael Reissner (reissner@tuwien.ac.at) and should include: one page CV; a list of publications with those involving the Mössbauer Effect highlighted; and one page statement of importance of research and significance of the Mössbauer Effect to the research. Self nominations are not permitted. The recipients of an IBAME Science Award (Young Scientist Award; Science Award) will be announced about six to eight months before ICAME2015. Awardees will be invited to present a talk at the next ICAME in September 2015 in Hamburg, Germany. Deadline for submission is October 1st, 2014. Make your nominations today.
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    133 Authors index Aguilar‐García, B. 19 Aguirre, W. 97 Aguirre‐Contreras, W. R. 32, 92 Akiyama, K. 25, 27, 104 Albornoz, M.F. 76 Albuquerque, A. S. 38 Amorim Lima, M. 39 Andrade, A.L. 47 André‐Filho, José 114 Appoloni, C.R. 59 Aquino, J. C. R. 20 Aragón, F. H. 20 Ardisson, J. D. 38, 47, 52, 55, 71, 76, 147, 148 Aristizabal, C. 73 Arnache, O. 81, 94 Arredondo S, P.I. 64 Ávila Pedraza, E.A. 60, 63 Avila, M. A. 93 Baggio‐Saitovitch, E.M. 12, 23, 36, 65, 66, 78,79, 84, 93 Balzuweit, K. 39, 101 Barrero, C.A. 12, 37, 64, 73, 78, 81, 84, 109, 118, 150 Bayer, P.S. 107 Beltrán, J. J. 10, 12, 37, 78, 84 Bengoa, J.F. 14 Benítez Rodríguez, E.D. 35 Betancourth, D. 95 Bravo Cabrejos, J.A 111,112 Bustamante Domínguez, A.G. 23 Bustamante, A. 85, 147 Bustos Rodríguez, H. 30, 33, 35, 60, 61, 63 Cabral Araújo, Tiago 68 Cabral‐Prieto, A. 19, 45, 57, 70, 74 Cabrera, M. 49, 93 Caetano, P.M.A. 10, 38 Camacho, K. I. 66, 79 Cardoso, C.A. 49 Carioca Fernandes, C. 39, 101 Carvalho Jr, L.B. 49 Castillo Weeks, M. 106 Cerón Loayza, María L. 111, 112, 113 Chillal, S. 36 Coaquira, J. A. H. 10, 20, 85, 87, 100, 102, 114 Cohen, R. 20 Cordeiro Silva, Gabriela 99 Corona Pérez, I. J. 57 Dias Filho, J. H. 39, 101 Domingues, R.Z. 47 Duarte Cavalcante, Luis Carlos 52, 54, 147 Ensuncho, L. 94 Escobar, L. 57, 74 Escudey, M. 76, 147 Fabris, J. D. 10, 47, 52, 54, 55, 68, 71, 76, 107, 118, 119, 121, 147, 148 Fagundes, M. 55, 147 Fajardo, Modesto 116 Félix, L. L. 114 Fernadez‐Outon, L.E. 38 Flores, E. 43 Floresta, D. L. 55, 147 Gaete, L. 76 García, K. E. 64, 73, 109 García‐R, G. 45 García‐Sosa, I. 19, 45, 74 Garg, V. K. 34, 85, 147, 148 Gattacceca, J. 56 Giffoni, M. 23 González Arias, J.U. 63 González Díaz, R. C. 57 González Neri, M. 57 Gouvêa, D. 20 Grag, V.K. 102 Granada, D. A. 95 Greneche, J.M. 64 Gvasaliya, S.N. 36 Hernández, T. 77 Herojit Singh, L. 34 Herrera, W. T. 10, 23, 66, 79 Hidalgo, P. 20 Huízar‐Félix, A. M. 77 Iida, Y. 104 Ikeoka, R.A. 59 Jaén, J.A. 7, 43, 106 Jiménez, M. 43 Klingelhöfer, Göstar 54 Kubuki, S. 10, 25, 27, 104 Landauro, C.V. 50 Legarra, E. 77 León Félix, L. 85, 100, 102 Litterst, F.J. 36 Litterst, J. 10, 23 López, J. L. 10, 39, 101 López, L.A. 94 López‐Castañares, R. 19, 70, 74 Lozano, D. Oyola 30, 35, 60, 61, 63, 95 Lushnikov, S.G. 36 Macedo, A. L. 71 Macedo, W.A.A. 38 Machala, Libor 13 Maciel, J.C. 49 Mantilla, J. 85, 100, 102 Marchetti, S.G. 14 Márquez, M. 109
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    134 Martínez Ovalle,S. A. 110 Martinez, A. I. 66, 79 Martinez, M. A. R. 85, 100, 114 Mastelaro, V.R. 107 Matos, P. R. 38 Matsuda, K. 27 Mejía, M. 51 Mena, David 116 Mercader, R.C. 7, 14, 150 Merces, A.A.D. 49 Merida, D. 77 Mesquita, João P. de 68 Mestnik‐Filho, José 114 Micklitz, H. 93 Monroy Guzman, F. 57 Morais, P.C. 85 Morales, L.A 81 Morales‐Gil, P. 65 Moreno, Maricel 110 Munayco, P. 59, 62 Munevar, J. 36, 93 Muñoz, A. 43 Nagamine, L.C.C.M. 20 Nava, N. 7, 57, 65, 74 Nishida, T. 25, 27, 104 Nomura, K. 12, 118 Olea‐Cardoso 19, 70, 74 Olea‐Mejía, O. 70 Olguín, M.T. 74 Oliveira, A. C. de 34, 85,102 Oliveira, Henrique dos S. 68 Oliveira, Luiz C. A. de 68 Oliveira, W. L. 71 Olzon‐Dionysio, D. 107 Olzon‐Dionysio, M. 49, 107 Ortega, C. 94 Ortíz Arcivar, G. 57 Osorio, J.A. 12, 37, 78, 84 Oyola Lozano, Dagoberto 10, 33, 60, 61 Paiva, D.L. 47 Paniago, R. 39, 101 Pariona, N. 66 Parise, M. 85 Passamani, Edson Caetano 31 Pati, S. S. 34 Pereira, M. C. 71, 147, 148 Pérez Alcázar, G. A. 7, 10, 35, 42, 60, 61, 63, 88, 91, 97, 116 Pérez de Berti, I.O. 14 Pérez‐Alcázar, G. A. 86 Piamba Jimenez, Jeferson 116 Piamba, J. F. 42, 86, 90, 91 Pillaca, M. 50 Pires, M. J. M. 68, 71, 107 Pizarro, C. 76 Plazaola, F. 77, 147 Punnoose, A. 12, 37 Quispe‐Marcatoma, J. 50, 66, 79 Ramos, J. 42 Reguera, Edilso 18 Reyes Caballero, F. 110 Ribeiro, R. 93 Rocha Cabrera, R. 50 Rochette, P. 56 Rodríguez, H. 95 Rojas Martínez, Y. A. 30, 33, 35, 60, 61, 63 Rojas, Y. A. 35, 61, 95 Ruiz Saldarriaga, E. 97, 98 Sá Oliveira, D. M. 39 Sá Teles, José J. 68 Salazar, H. 109 Salcedo‐Castillo, U. 70 Sánchez Shepa, Héctor 116 Sánchez, H. 42, 78 Sánchez, L.C. 12, 78, 84, 94 Sanchez, P. 76 Sandoval‐Nandho, A. 19 Santos Valladares, L. De Los 85 Santos, E. Dos 56, 59, 62 Schönhöbel, A.M. 32, 92 Scorzelli, R. B. 56, 59, 62, 147, 148 Shaplygina, T. 36 Sharma, Virender K. 13 Shigeyosi, W. T. 49, 107 Sierra, G.A. 81 Sinkó, K. 25 Siskova, Karolina 13 Soares Meneses Lage, Maria Conceição 54 Sousa Bezerra da Silva, Heralda Kelis 52 Souza Dinóla, Isabel Cristina 99 Souza, S. D. de 49, 107 Souza, S. de 107 Tabares, J. A. 43, 86, 88, 97, 110 Takahashi, Y. 10, 25 Trujillo Hernandez, J. S. 88, 97 Trujillo, A. 51 Uemura, Y. J. 93 Urquijo, J.P. 83 Vargas Fontalvo, F. M. 60, 63 Velásquez, A. A. 83 Venegas, S. 83 Wright, V. 51 Xingu‐Contreras, E. 45 Zamora, L. 97 Zamora, Ligia E. 86 Zboril, Radek 13 Zeballos‐Velásquez, E. 51 Zheludev, A. 36
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