In recent times perovskite materials are extensively studied and have attracted much attention because they exhibit interesting the properties, showing potential applications in commercial, technical and biomedical. In Vietnam, perovskite materials be of interest research and applications are strong but with major research direction is to go deep into the electrical properties and the magnetic properties. The Lanthanum Strontium manganite is a perovskite-based crystal-structured ceramic material with the formula of La1-xSrxMnO3, where x describes the doping ratio. It has attracted much attention due to its good magnetic, electrical, and catalytic properties and is becoming an attractive possibility material in several biomedical applications, particularly with nano-size. In industry, this material is commonly used in as a cathode material in commercially produced solid oxide fuel cells. In this thesis, we present the Perovskite nanoparticles La1-xSrxMnO3 were successfully synthesized of the nanosize La1-xSrxMnO3 at x = 0; 0.1; 0.2; 0.3 and 0.4 which prepared by a modified sol-gel method. Structure and magnetic properties of them were systematically investigated in dependence on doped Sr ratio x. The structure was investigated by XRD and show slightly changed but magnetic properties varied strongly with changing the doping ratio x. Magnetic properties of samples were studied by Vibrating Sample Mode of Physical Properties Measurement System show at the room temperature, the samples show superparamagnetic properties with high saturated magnetization MS of 57 emu/g which strongly dependents on the doped Sr ratio x.
Perovskite: introduction, classification, structure of perovskite, method to synthesis, characterization by XRD and UV- vis spectroscopy , lambert beer's law, material properties and advantage and application.
Optical band gap measurement by diffuse reflectance spectroscopy (drs)Sajjad Ullah
Introduction to Optical band gap measurement
by electronic spectroscopy and diffuse reflectance spectroscopy (DRS) with comparison of the results obtained suing different equation and measurement techniques.
The role of scattering in extinction of light as it passes through media is briefly discussed.
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
Perovskite: introduction, classification, structure of perovskite, method to synthesis, characterization by XRD and UV- vis spectroscopy , lambert beer's law, material properties and advantage and application.
Optical band gap measurement by diffuse reflectance spectroscopy (drs)Sajjad Ullah
Introduction to Optical band gap measurement
by electronic spectroscopy and diffuse reflectance spectroscopy (DRS) with comparison of the results obtained suing different equation and measurement techniques.
The role of scattering in extinction of light as it passes through media is briefly discussed.
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
A perovskite solar cell is a type of solar cell which includes a perovskite structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material, as the light-harvesting active layer.
This presentation summarizes history and recent development of perovskite solar cells. If you have any questions or comments, you can reach me at agassifeng@gmail.com
NQR - DEFINITION - ELECTRIC FIELD GRADIENT - NUCLEAR QUADRUPOLE MOMENT - NUCLEAR QUADRUPOLE COUPLING CONSTANT - PRINCIPLE OF NQR - ENERGY OF INTERACTION - SELECTION RULE - FREQUENCY OF TRANSITION - APPLICATIONS
Perovskite Solar Cells
a short general overview presentation
hadi maghsoudi
device structure
crystal structure
preparation synthesis method
review papers
This includes what is Quantum Dots and their properties ,types of synthesis methods of nano materials such as top down, bottom up etc.It includes few things about Carbon Quantum Dots.
Hot wall reactor is a high temperature chamber in which the substrate is placed for coating. In this reactor including the substrate, all other parts (inlet and outlet tubes) inside the chamber get coated.
Fabrication and Characterization of 2D Titanium Carbide MXene NanosheetsBecker Budwan
Typically, 2D free-standing crystals exhibit different properties from those of 3D counterparts. In this work, 2D nanosheets of Ti3C2 are synthesized by the room temperature exfoliation of Ti3AlC2 in hydrofluoric acid. Al is extracted from Ti3AlC2 and a new 2D material that we call MXene is formed to emphasize its graphene-like morphology. The treated powders can be used in the fabrication of Li-ion batteries and capacitors. A NSEM image of the treated powder shows the influence of HF treatment on the basal planes. Furthermore, XRD results shows the broadening of the peaks and loss of diffraction signal in the out-of-plane direction owing to exfoliation.
A perovskite solar cell is a type of solar cell which includes a perovskite structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material, as the light-harvesting active layer.
This presentation summarizes history and recent development of perovskite solar cells. If you have any questions or comments, you can reach me at agassifeng@gmail.com
NQR - DEFINITION - ELECTRIC FIELD GRADIENT - NUCLEAR QUADRUPOLE MOMENT - NUCLEAR QUADRUPOLE COUPLING CONSTANT - PRINCIPLE OF NQR - ENERGY OF INTERACTION - SELECTION RULE - FREQUENCY OF TRANSITION - APPLICATIONS
Perovskite Solar Cells
a short general overview presentation
hadi maghsoudi
device structure
crystal structure
preparation synthesis method
review papers
This includes what is Quantum Dots and their properties ,types of synthesis methods of nano materials such as top down, bottom up etc.It includes few things about Carbon Quantum Dots.
Hot wall reactor is a high temperature chamber in which the substrate is placed for coating. In this reactor including the substrate, all other parts (inlet and outlet tubes) inside the chamber get coated.
Fabrication and Characterization of 2D Titanium Carbide MXene NanosheetsBecker Budwan
Typically, 2D free-standing crystals exhibit different properties from those of 3D counterparts. In this work, 2D nanosheets of Ti3C2 are synthesized by the room temperature exfoliation of Ti3AlC2 in hydrofluoric acid. Al is extracted from Ti3AlC2 and a new 2D material that we call MXene is formed to emphasize its graphene-like morphology. The treated powders can be used in the fabrication of Li-ion batteries and capacitors. A NSEM image of the treated powder shows the influence of HF treatment on the basal planes. Furthermore, XRD results shows the broadening of the peaks and loss of diffraction signal in the out-of-plane direction owing to exfoliation.
K2O - CdO - B2O3 – SiO2glasses containing different concentrations of MnO2 have been prepared. The Physical properties of the glasses are studied from their density. The studies have been analysed in the light of different oxidation states of manganese ion with the aid of the data from optical absorption. The analysis shows that manganese ions exist mainly in Mn2+ state, occupy tetrahedral positions and increase the insulating strength of the glass if MnO2 is present in smaller concentrations.
Implant dentistry is growing well in Myanmar. As a faculty member and a dentist who is specialized in Prosthetic Dentistry including Dental Implant, the presenter notice that we have to move another one step...usage of bio-material... in clinical practice.
A dental implant (also known as an endosseous implant or fixture) is a surgical component that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biologic process called osseointegration where materials, such as titanium, form an intimate bond to bone.
We are going to discuss the four Biomaterials and their Dental Applications, the Advantages and Disadvantages of each Material.
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Paul Ducheyne (University of Pennsylvania, USA) on September 29, 2015, in Rio de Janeiro (Brazil).
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass SystemSidek Aziz
Synthesis and Elastic Studies of Lead Boro-Tellurite Glass System presented Seminar Kebangsaan Aplikasi Sains dan Matematik 29-30 October 2013 ata UTHM Johor
Facile Synthesis and Characterization of Pyrolusite, β-MnO2, Nano Crystal wit...Editor IJCATR
MnO2 nanoparticles have been synthesized by a simple combustion method using MnSO4.4H2O. The crystalline phase, morphology, optical property and magnetic property of the as prepared nanoparticle were characterized using XRD, FT-IR, FT-Raman, SEM, UV-Vis, PL and VSM respectively. Structural studies by XRD indicate that the synthesized material as tetragonal rutile crystal structure. FT-IR and FT-Raman analysis revealed the stretching vibrations of metal ions in tetrahedral co-ordination confirming the crystal structure. The PL and UV analysis having an emission band at 390 nm, showed a prominent blue peak at 453 nm as well as a green emission lines at 553 nm with band gap energy of 3.2eV. Magnetic measurements indicate that the Néel temperature of the β-MnO2 structures is 92.5K for Hc = 100 Oe which showed antiferromagnetic behaviour.
Facile Synthesis and Characterization of Pyrolusite, β- MnO2, Nano Crystal wi...Editor IJCATR
MnO2 nanoparticles have been synthesized by a simple combustion method using MnSO4.4H2O. The crystalline phase,
morphology, optical property and magnetic property of the as prepared nanoparticle were characterized using XRD, FT-IR, FTRaman,
SEM, UV-Vis, PL and VSM respectively. Structural studies by XRD indicate that the synthesized material as tetragonal rutile
crystal structure. FT-IR and FT-Raman analysis revealed the stretching vibrations of metal ions in tetrahedral co-ordination confirming
the crystal structure. The PL and UV analysis having an emission band at 390 nm, showed a prominent blue peak at 453 nm as well as
a green emission lines at 553 nm with band gap energy of 3.2eV. Magnetic measurements indicate that the Néel temperature of the β-
MnO2 structures is 92.5K for Hc = 100 Oe which showed antiferromagnetic behaviour
Structural, Electrical and Magnetotransport properties of La0.7Ca0.2Sr0.1MnO3...IOSR Journals
The sample of manganite perovskite oxide La0.7Ca0.2Sr0.1MnO3 has been prepared by solution combustion synthesis. The synthesized sample has been pelletized and further sintered at 8000C for 8 hours. The XRD pattern reveals that the samples are of single phase nature with orthorhombic structure and the diffraction patterns can be indexed with the pbnm space groups. The crystallite sizes calculated from broadening of XRD peaks using Scherrer’s formula were about 18 nm. Resistivity measurements were performed in the temperature range 2K under 3, 5, 10 and 14 T field using PPMS. Magnetoresistance shows a shift in metal-insulator transition temperature from ~213 K at zero field to ~250 K at 14T. MR value decreases as the temperature increases and at 300 K maximum value of MR is found to be ~ 22% for an applied field of 14 T. MR of ~ 28% is observed at 230 K. MR of ~ 35% is observed at 150 K in an applied field of 14 T and MR has negative sign
Simple and Effective Method of the Synthesis of Nanosized Fe2O 3particlesIOSR Journals
Abstract: Nanosized Iron oxide is prepared by using precipitation method from iron nitrate and liquid ammonia. Thermal analysis shows that synthesized iron oxide shows some weight loss and oxide undergoing decomposition, dehydration or any physical change from TGA curve we observe that Iron oxide shows stable weight loss above 4000C. In DTA curve also, there is exothermic and endothermic peak. Which shows phase transition, solid state reaction or any chemical reaction occurred during heating treatment. Morphology is observed by scanning electron microscopy (SEM) shows particles are nanosized. Further morphology observation by Transmission Electron Microscopy (TEM) revels that Iron Oxide has the corundum (Al2O3) structure. Magnetic measurements shows that iron oxide has five unpaired electron and strongly paramagnetic character.
Synthesis and Study on Structural, Morphological and Magnetic properties of n...Editor IJCATR
Mn3O4 nanoparticles were prepared by co-precipitation method followed by annealing of samples at 300 °C for 2 hours. The
samples were characterized to find the structural, functional, optical, morphological, compositional and magnetic properties by PXRD,
FTIR, Micro-Raman, HRSEM, TEM, XPS, EDX and VSM respectively. Structural studies by PXRD indicate that the annealing has
strongly influenced the phase transition showing two coexisting phases of Mn2O3 and Mn3O4. Micro-Raman spectra showed the
presence of A1g mode of vibration corresponding to Mn3O4 phase. Magnetic studies of the as synthesized Mn3O4 nanoparticles depict
paramagnetic behavior at room temperature.
Introduction to nanoscience and nanotechnologyaimanmukhtar1
Introduction of nanoscience/nanotechnology ,properties/potential applications of nanomaterials and electrodeposition of metal single component and alloy nanowires in AAO template
Structural and magnetic properties on F-doped LiVO2 with two-dimensional tria...Yang Li
The layered oxide LiVO2 recently has received more attention due to its interesting structural and magnetic behaviors involving the two-dimensional magnetic frustration in these systems. We synthesized a series of F-doped LiVO2 samples, and reported the F-doping effect on the structure and transition temperature Tt. The samples LiVO2-xFx (x=0, 0.1, 0.2 and 0.3) were characterized by X-ray diffraction, scanning electron microscope (SEM), differential scanning calorimetry (DSC), magnetic susceptibility and specific heat measurement. The structural analysis shows that with increasing x, the ratio of lattice parameter c/a increasing, i.e. in the a-b plane the lattice is compressed while in the c-axis direction the lattice expands. The DSC measurements show that a first-order phase transition happens at around 500 K, and the thermal hysteresis around phase transition temperature Tt increases with increasing x. Substitution of O with F ions results in a change of two dimensional characteristics and the distortion of the VO6 block in structure, which significantly influence the magnetic ordering transition temperature Tt.
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
This presentation is about phtoocatalytic process and nanomaterials as photocatalyst. This is useful in the treatment of wastewater and environmental remediation applications.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Synthesis and charaterization of la1 x srxmno3 perovskite nanoparticles
1. LOGO
Synthesis and Charaterization
of La1-xSrxMnO3 Perovskite
nanoparticles (x from 0 to 0.4)
Presenter : Tran Thi Mai – K55 IP
Supervisor: Dr. Nguyen Hoang Nam
Luu Manh Quynh
3. I. Introduction
1.1. The perovskite structure ABO3
perovskite has cubic structure and the cubic
unit cell has the network parameters is:
a = b = c ;
At the peak position of the cubic is the
cation A that around is the position of the
oxygen anion (located in the center of the
cubic face). The cation B is located in the
center cubic
The most important characteristic of the perovskite structure ABO3 is the
existence of the octahedral BO6
α = β = γ = 90o
4. I. Introduction
Crystal structure which can be changed from cubic to other formats such as
rhombohedral or orthorhombic when the ion A or ion B is changed by other
elements.
La1-xSrxMnO3 is a perovskite has the types
structure ABO3, in which the La ions are
replaced partially by Sr ions.
Due to structural differences have caused
lattice distortion and make the structure of
materials are changed from cubic to other
formats.
5. I. Introduction
2. Jahn – Teller distortion
When the doped or replacement, the ideal perovskite crystal structures will be
changed (occurs distortion)
Jahn – Teller effects occurs in a metal ions contained the odd number of the
electronic in the eg levels. However, this effect also occurs in compounds which
have the octahedral structure
Jahn – Teller distortion in the perovskite materials
When the octahedral structure change
will make to the length of association
changed according to the axis
6. I. Introduction
3. magnetic properties in the perovskite materials system La1-xAxMnO3
LaMnO3 compounds show antiferromagnetic properties due to the super-
exchange interaction (SE) between ions Mn3+. When doped ion alkanline metal
elements A2+ (Sr2+) into position of ions rare earth La3+, to ensure charge
neutralize conditions, the partial charge of ion Mn3+ transfer into ion Mn4+.
While the perovskite manganese not doped have dielectric anti –ferromagnetic
properties, the appearance of Mn4+ make the electrical conductivity increases
and appearance the ferromagnetic properties. When the doped concentration is
increased, the conductivity of the material also increases, up to a certain value,
the material will good conductivity as metal and to express strong ferromagnetic
properties
7. I. Introduction
5. The fabrication technology
The Solid phase reaction method (ceramic method)
The coprecipitation method
The hydrothermal method
The reaction Milling method
The sol – gel method
8. I. Introduction
The sol – gel method:
The process of creating materials by the sol - gel method consists of
4 main stages:
Creating solution (sol)
Gelled and shaped
Drying
Conglomeration
Các bước tạo vật liệu bằng phương pháp sol – gel
The main benefits of sol–gel processing are the high purity and uniform
nanostructure achievable at low temperatures.
9. II. Experimental
1. The instruments and chemicals
chemicals
Lanthanum oxide
(La2O3)
Strontium carbonate
(SrCO3)
Manganese nitrate
(Mn(NO3)2.4H2O)
Citric acid (CA.1H2O)
Nitric acid (HNO3)
instruments
Glass, pipet,
Thermometer
Magnetic stirrer (RH
basic KTC)
Drying furnace
(1350FX – 2E Model)
Calcining furnace
(CD 1600X CHIDA
10. II. Experimental
some image of instruments are used in the process
Magnetic stirrer
(RH basic KTC)
Drying furnace
(1350FX – 2E Model)
Calcining furnace
(CD 1600X CHIDA)
11. II. Experimental
CA
Sr(NO3)2 Mn(NO3)2
La(NO3)3
Stirring at 80oC
Sol gel compounds
xerogel
Fabrication process of material by sol – gel method
Drying Preheating Heating
at 1000o Cat 300o Cat 120o C
2. Fabrication process of material
12. II. Experimental
3. Some illustrative photos
a) b)
c)
Figure: a) sol is obtained after stirring at 80o C
b) and c) the product respectively obtained after
preheating at 300o C and heating at 1000o C
14. III. Results and discussion
10 20 30 40 50 60 70 80
0
100
200
300
400
500
600
700
800
900
Intensity(a.u)
2(degree)
x=0
x=0.1
x=0.2
x=0.3
x=0.4
(102)
(110) (104)
(202)
(006)
(204)
(212)
(116)
(214) (300)
(220) (208)
XRD patterns of La1-xSrxMnO3 nanoparticles with x = 0, 0.1, 0.2, 0.3 and 0.4
15. III. Results and discussion
Table 1. The lattice parameters of the La1-xCaxMnO3 samples
with x from 0 to 0.4
Lattice parameters
Volume of cell
unit (Å3)
Sample a(Å) b(Å) c(Å)
x=0 5.48 5.49 7.71 231.96
x=0.1 5.54 5.45 7.92 239.13
x=0.2 5.49 5.50 7.76 234.31
x=0.3 5.49 5.48 7.82 235.26
x=0.4 5.47 5.46 7.91 236.24
16. III. Results and discussion
From XRD using the Debye – Scherrer formula:
Sample d(102) d(110) d(202) d(204)
d(212)
d(214)
x=0 29.6nm 17.5nm 30.9nm 28.4nm
13.0nm
22.5nm 23.7nm
x=0.1 28.2nm 17.9nm 25.7nm 28.7nm
14.7nm
21.3nm 22.7nm
x=0.2 26.7nm 19.3nm 19.5nm 25.5nm
17.4nm
14.5nm 20.5nm
x=0.3 24.7nm 19.4nm 18.4nm 24.6nm
16.5nm
14.1nm 19.6nm
x=0.4 27.0nm 22.7nm 19.0nm 25.0nm
15.8nm
15.4nm 20.8nm
The size of crystallites of La1-xSrxMnO3 with x from 0 to 0.4 as the table 2.
Table 2: Size of crystallites of La1-xSrxMnO3
17. III. Results and discussion
2. Analysis of Scanning electron micrographs (SEM), and
energy dispersive x – ray spectra (EDS)
SEM image and EDS spectra of the sample without doped (LaMnO3)
18. III. Results and discussion
SEM image and EDS spectra of the sample La0.9Sr0.1MnO3
19. III. Results and discussion
SEM image and EDS spectra of the sample La0.8Sr0.2MnO3
20. III. Results and discussion
SEM image and EDS spectra of the sample La0.7Sr0.3MnO3
21. III. Results and discussion
SEM image and EDS spectra of the sample La0.6Sr0.4MnO3
22. III. Results and discussion
a)
d)c)
b)
SEM images of La1-xSrxMnO3
with x = 0.1, 0.2, 0.3 and 0.4
annealed at 1000˚C for 2 h
shown in order from left to
right and top to bottom
23. IV. Conclusion
In this thesis, we have successfully fabricated La1-xSrxMnO3
perovskite materials that nanoscale by the sol-gel method, doped
with Sr ratio from x = 0.1 0.4.
The structure analysis shows that the structure of samples is
typical perovskite structure and the Sr was successfully doped into
sample. The structure of sample have small changes with changing
doping ratio x.
In this thesis, I only mention the perovskite compounds fabricated by sol-gel method
The sol-gel method is a process chain of chemical reactions starting from the sol liquid of precursor are liquid and solid ...the particles sol hydrolysis reaction and condensation to form gel. Gel were dried, calcined to remove the organic matter and the formation of the final product in the solid state
It can be seen that the XRD pattern of sample with x = 0 clearly shows double peaks which are assigned to rhombohedral structure reflections such as double peak of (220), (208) reflections. When Sr was doped into sample, those peaks were not clearly separated with each other like sample with x = 0, such as the sample with x = 0.4
XRD patterns indicated that La1-xSrxMnO3 nanoparticles crystallized in typical ABO3 perovskite rhombohedral structure. Thus, we can calculate the lattice constants of the La1-xCaxMnO3 samples with doped ratio x from 0 to 0.4 as table 1.
the energy – dispersive x-ray spectra (EDS) of the doped composite for x from 0 to 0.4 shows the peaks are La, O, Mn, and Sr, which also supports the presence of Sr2+ in the doped composites
From the SEM image of the samples with x from 0 to 0.4, It reveals that the particles have particle sizes of much larger than the crystallites sizes that calculated from XRD results.
we can see particles conglomerated to clusters. It was not created clear shapes. Particles fairly even and have complicated shape.