1. The document describes a new technique for measuring the giant magnetoresistance (GMR) of individual multilayer nanowires inside a scanning electron microscope (SEM).
2. Using nanomanipulators equipped with sharp tips, the resistance of NiFe/Pt multilayer nanowires can be measured at specific sites as an external magnetic field is varied.
3. Measurements of ~70nm diameter NiFe/Pt nanowires showed a GMR effect of up to 5.8% depending on layer thicknesses and field orientation. This new in-situ method allows precise characterization of nanowire magnetoresistance related to microstructure, geometry, and field orientation.
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRESijoejournal
Copper nanowires were prepared through electrochemical template synthesis using Nucleopore polycarbonate membranes having nominal pore sizes of 800nm and 15nm diameter. The 800nm and 15nm nanowires thus grown were viewed under SEM and TEM respectively, while their FCC crystallographic structure was confirmed through X-ray and electron diffraction patterns. The X-ray diffraction peaks indicated strong texturing for (200). The texturing was found to reduce significantly upon exposure to ultraviolet radiation.
Biomedical Application of Magnetic NanomaterialsMahmudun Nabi
This document discusses a project to characterize magnetic nanoparticles for use in biomedical applications. The objectives are to:
1. Characterize the magnetic nanoparticles and study their AC susceptibility, size distribution, magnetic properties, and relaxation to determine parameters like magnetic moment and blocking temperature.
2. Develop a system to detect biological targets using magnetic nanoparticles and improve the system's sensitivity.
3. Validate the magnetic immunoassay technique by comparing results to conventional methods and analyzing outcomes for biological targets.
The document describes a family of microinstruments being developed for use in space missions. The instruments use magneto-optic thin film sensors to perform tasks like non-destructive testing of spacecraft components, detecting electromagnetic fields, monitoring biomagnetic fields, and optical signal processing. Each sensor is based on a proprietary Fe-Ga thin film material and uses polarized light and a spatial light modulator. The sensors can detect magnetic fields as small as 10-7 Oersted and have applications in areas like defect detection, energy generation, medicine, and neural networks. The technology provides advantages over existing non-destructive testing methods by directly imaging defects in real-time with high resolution and low false readings.
Study of magnetic and structural and optical properties of Zn doped Fe3O4 nan...Nanomedicine Journal (NMJ)
Objective(s):
This paper describes synthesizing of magnetic nanocomposite with co-precipitation
method.
Materials and Methods:
Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125) were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and UV-Vis spectroscopy.
Results:
results obtained from X-ray diffraction pattern have revealed the formation of single phase nanoparticles with cubic inverse spinal structures which size varies from 11.13 to 12.81 nm. The prepared nanoparticles have also possessed superparamagnetic properties at room temperature and high level of saturation magnetization with the maximum level of 74.60 emu/g for x=0.075. Ms changing in pure magnetite nanoparticles after impurities addition were explained based on two factors of “particles size” and “exchange interactions”. Optical studies results revealed that band gaps in all Zn-doped NPs are higher than pure Fe3O4. As doping percent increases, band gap value decreases from 1.26 eV to 0.43 eV.
Conclusion:
These magnetic nanocomposite structures since having superparamagnetic property
offer a high potential for biosensing and biomedical application.
STM Observation of the Si(111) - (7×7) Reconstructed Surface Modified by Exce...IJECEIAES
The electronic properties of semiconductor surfaces change readily upon changing the carrier densities by controlling the dopant concentration. Additionally, excess dopant atoms can exert electric field which would affect the molecular adsorption process and could be used to manipulate the dynamic movement of confined molecules. A mechanism can be developed to control the molecular dynamic movement on modified semiconductor surface by dopants thus changing the effect of the electric field on the active molecules. In this study, the Si(111) surface was doped with phosphorus excessively using thermal diffusion process. The surface was then reconstructed to the 7×7 configuration via heating under UHV conditions and then studied through STM and STS techniques. The protrusions due to surface and subsurface P atoms appear brighter due to the lone electron pair. The 7×7 reconstruction would be destabilized after a critical P substitution of Si-adatom concentration due to high surface strain result in P-terminated (6√3×6√3)R30º reconstruction.
This document discusses various characterization techniques for nanoparticles. It describes microscopy methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning tunneling microscopy (STM) that can be used to determine nanoparticle size, shape, composition and crystalline structure at high resolution. Spectroscopy methods like X-ray diffraction (XRD), small angle X-ray scattering (SAXS), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, and Fourier transform infrared spectroscopy (FT-IR) are also outlined for analyzing nanoparticle properties. The key techniques of SEM, TEM, XRD and SAXS are then explained in more detail regarding their basic principles and what types of nanoparticle information can be obtained
This document discusses the integration of a layered ferromagnetic composite material into a microwave propagation structure to enable tunable microwave device applications. The material combines the large saturation magnetization of ferromagnetic material with the low loss of dielectrics. Electromagnetic analysis was carried out to understand how the material properties are affected by the microwave field pattern and dc magnetic fields. Experimental results demonstrated tunable band stop filter and switch devices using the material, with over 50% tunability achieved in the filter using a 250 Oe dc field.
This document provides an overview of magnetic nanocomposite materials. It discusses how nanocomposite materials with magnetic particles embedded in a matrix can have properties different from conventional composites due to interactions at the nanoscale. The document then reviews the history of magnetic nanocomposites, including early amorphous alloys and more recent developments like FINEMET, NANOPERM, and HITPERM which use crystalline nanoparticles embedded in an amorphous matrix. Recent advances in preparation of functional nanocomposites and hybrid materials are also summarized, including core-shell nanoparticles, colloidal crystals, mesoporous composites, and functional magnetic polymers.
EFFECT OF ULTRAVIOLET RADIATION ON STRUCTURAL PROPERTIES OF NANOWIRESijoejournal
Copper nanowires were prepared through electrochemical template synthesis using Nucleopore polycarbonate membranes having nominal pore sizes of 800nm and 15nm diameter. The 800nm and 15nm nanowires thus grown were viewed under SEM and TEM respectively, while their FCC crystallographic structure was confirmed through X-ray and electron diffraction patterns. The X-ray diffraction peaks indicated strong texturing for (200). The texturing was found to reduce significantly upon exposure to ultraviolet radiation.
Biomedical Application of Magnetic NanomaterialsMahmudun Nabi
This document discusses a project to characterize magnetic nanoparticles for use in biomedical applications. The objectives are to:
1. Characterize the magnetic nanoparticles and study their AC susceptibility, size distribution, magnetic properties, and relaxation to determine parameters like magnetic moment and blocking temperature.
2. Develop a system to detect biological targets using magnetic nanoparticles and improve the system's sensitivity.
3. Validate the magnetic immunoassay technique by comparing results to conventional methods and analyzing outcomes for biological targets.
The document describes a family of microinstruments being developed for use in space missions. The instruments use magneto-optic thin film sensors to perform tasks like non-destructive testing of spacecraft components, detecting electromagnetic fields, monitoring biomagnetic fields, and optical signal processing. Each sensor is based on a proprietary Fe-Ga thin film material and uses polarized light and a spatial light modulator. The sensors can detect magnetic fields as small as 10-7 Oersted and have applications in areas like defect detection, energy generation, medicine, and neural networks. The technology provides advantages over existing non-destructive testing methods by directly imaging defects in real-time with high resolution and low false readings.
Study of magnetic and structural and optical properties of Zn doped Fe3O4 nan...Nanomedicine Journal (NMJ)
Objective(s):
This paper describes synthesizing of magnetic nanocomposite with co-precipitation
method.
Materials and Methods:
Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125) were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and UV-Vis spectroscopy.
Results:
results obtained from X-ray diffraction pattern have revealed the formation of single phase nanoparticles with cubic inverse spinal structures which size varies from 11.13 to 12.81 nm. The prepared nanoparticles have also possessed superparamagnetic properties at room temperature and high level of saturation magnetization with the maximum level of 74.60 emu/g for x=0.075. Ms changing in pure magnetite nanoparticles after impurities addition were explained based on two factors of “particles size” and “exchange interactions”. Optical studies results revealed that band gaps in all Zn-doped NPs are higher than pure Fe3O4. As doping percent increases, band gap value decreases from 1.26 eV to 0.43 eV.
Conclusion:
These magnetic nanocomposite structures since having superparamagnetic property
offer a high potential for biosensing and biomedical application.
STM Observation of the Si(111) - (7×7) Reconstructed Surface Modified by Exce...IJECEIAES
The electronic properties of semiconductor surfaces change readily upon changing the carrier densities by controlling the dopant concentration. Additionally, excess dopant atoms can exert electric field which would affect the molecular adsorption process and could be used to manipulate the dynamic movement of confined molecules. A mechanism can be developed to control the molecular dynamic movement on modified semiconductor surface by dopants thus changing the effect of the electric field on the active molecules. In this study, the Si(111) surface was doped with phosphorus excessively using thermal diffusion process. The surface was then reconstructed to the 7×7 configuration via heating under UHV conditions and then studied through STM and STS techniques. The protrusions due to surface and subsurface P atoms appear brighter due to the lone electron pair. The 7×7 reconstruction would be destabilized after a critical P substitution of Si-adatom concentration due to high surface strain result in P-terminated (6√3×6√3)R30º reconstruction.
This document discusses various characterization techniques for nanoparticles. It describes microscopy methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning tunneling microscopy (STM) that can be used to determine nanoparticle size, shape, composition and crystalline structure at high resolution. Spectroscopy methods like X-ray diffraction (XRD), small angle X-ray scattering (SAXS), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, and Fourier transform infrared spectroscopy (FT-IR) are also outlined for analyzing nanoparticle properties. The key techniques of SEM, TEM, XRD and SAXS are then explained in more detail regarding their basic principles and what types of nanoparticle information can be obtained
This document discusses the integration of a layered ferromagnetic composite material into a microwave propagation structure to enable tunable microwave device applications. The material combines the large saturation magnetization of ferromagnetic material with the low loss of dielectrics. Electromagnetic analysis was carried out to understand how the material properties are affected by the microwave field pattern and dc magnetic fields. Experimental results demonstrated tunable band stop filter and switch devices using the material, with over 50% tunability achieved in the filter using a 250 Oe dc field.
This document provides an overview of magnetic nanocomposite materials. It discusses how nanocomposite materials with magnetic particles embedded in a matrix can have properties different from conventional composites due to interactions at the nanoscale. The document then reviews the history of magnetic nanocomposites, including early amorphous alloys and more recent developments like FINEMET, NANOPERM, and HITPERM which use crystalline nanoparticles embedded in an amorphous matrix. Recent advances in preparation of functional nanocomposites and hybrid materials are also summarized, including core-shell nanoparticles, colloidal crystals, mesoporous composites, and functional magnetic polymers.
Structural and Optical properties of Multiwalled Carbon Nanotubes Modified by...TELKOMNIKA JOURNAL
Structure, chemical, and physical properties of Multiwalled Carbon Nanotubes (MWCNTs) after
modification by dielectric barrier discharge (DBD) at atmospheric pressure is investigated using
Transmission Electron Microscopy (TEM), Raman and Uv-vis-NIR spectroscopy. Effects of plasma
treatment time on MWCNTs are analyzed. TEM result shows that during the short period of plasma
treatment time of 5 minutes, the tube surface experienced a few damages. With increase in plasma
treatment time, the tube surface is damaged to a certain extent. Intensity ratio, ID/IG through Raman
analysis shows a good agreement with TEM. The values of ID/IG of the modified MWCNTs are larger than
those of pristine MWCNTs. An increase of ID/IG indicates that considerable defects are produced on the
surfaces of MWCNTs. The treated MWCNTs has energy band gap compared to zero band gap of
untreated MWCNTs. It is believed that the defect site of MWCNTs can modify the electronics properties of
MWCNTs from being metallic to semiconducting structure, which is applicable for almost all electronics
device applications.
Greener cum chemical synthesis and characterization of Mg doped ZnS nanoparti...IJERA Editor
In the present investigations, high-quality Mg doped ZnS nanoparticles were synthesized by Greener cum
chemical process with the assistance of polyvinyl pyrrolidone (PVP) with two different Mg concentrations.
Doping of Mg metal in nanoparticles were found to be a good technique for tuning the band gap of ZnS
nanoparticles. Simultaneously, Mg doping also inhibited the growth of particle size and it decreased from 33.2
nm to 18.3 nm with the increase in doping concentration from 0% to 5%. Band gap was found to rise from 3.12
eV to 3.38 eV and photoluminescence studies exposed that visible Photoluminescence (PL) emission was
improved with doping concentration. The nanoparticles have been characterized by Field Emission Scanning
Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy,
Ultra Violet visible (UV–vis) spectroscopy, and Energy Dispersive X-ray Analysis (EDAX).
Enhanced Exchange Pinning Field For Fe Mn Spin Valvesguestc57e7ed
This document discusses enhanced exchange pinning fields observed in spin-valve structures with ultra-thin magnetic pinned layers and FeMn antiferromagnetic layers. Three material systems - CoNiFe/Cu, NiFe/Cu, and CoFe/Cu - were investigated. Spin-valves with pinned layers as thin as 0.5 nm exhibited exchange pinning fields as high as 800-900 Oe for CoNiFe/Cu and CoFe/Cu multilayers, while NiFe/Cu multilayers achieved a pinning field of around 500 Oe. Using ultra-thin pinned layers reduced demagnetizing effects and improved spin-valve performance in terms of linearity.
The document summarizes a study of the dielectric properties of nano-crystalline Mn-Zn ferrites. Samples of ZnxMn1-xFe2O4 where x ranges from 0.2 to 0.8 were synthesized using a solid-state route and characterized. The ac conductivity σ, dielectric constant ε', dielectric loss ε'', and loss tangent tan δ were measured from 100 Hz to 20 MHz. ε' and ε'' decreased with increasing frequency. σ was nearly frequency independent below 1 MHz and increased sharply above. The maximum dielectric constant and conductivity occurred for x=0.2, attributed to space charge polarization. The conduction mechanism was explained by electron hopping between Fe2+ and Fe
This document summarizes the presentation given by Kanupriya on the properties of nanomaterials. It discusses how the properties of materials change from bulk to nano size, including becoming transparent, stronger, and more chemically reactive. It specifically examines how optical, magnetic, and chemical properties are affected by the nano size. Optical properties depend on quantum confinement and surface plasmon resonance. Magnetic properties transition from ferromagnetic to superparamagnetic. Chemical reactivity increases due to more surface atoms. A variety of nanomaterials like quantum dots and metallic nanoparticles were highlighted.
This document discusses the application of a ferromagnetic composite material in tunable microwave devices. Specifically:
- The composite material consists of ferromagnetic and insulating thin film layers that exhibit tunable intrinsic impedance when a DC magnetic field is applied.
- Several microwave devices were demonstrated using this composite material, including a tunable bandstop filter with 50% tunability, phase shifters with figures of merit of 35 deg/dB around 3 GHz and 7.8 deg/dB in the X band, and a magnetic switch with over 25 dB isolation and less than 1 dB insertion loss.
- The tunable behavior results from changes in the ferromagnetic resonance frequency of the composite material under an applied magnetic field, which
This document describes magnetic tweezers, which are instruments that use magnetic fields to manipulate biomolecules. Magnetic tweezers typically exert piconewton forces on superparamagnetic beads attached to molecules like DNA or proteins to study their mechanical properties. They consist of magnets above a microscope that tracks bead position. Magnetic tweezers allow studying properties of single molecules and complexes by twisting or stretching molecules between a surface and bead. They have high resolution but low throughput. Recent advances aim to improve fields and resolution for diverse single molecule applications.
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.
Modulus spectroscopy study on Ferroelectric Lithium and Titanium modified Lea...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a Selective Filter based on 2D Photonic Crystals Materials IJECEIAES
Two dimensional finite differences temporal domain (2D-FDTD) numerical simulations are performed in cartesian coordinate system to determine the dispersion diagrams of transverse electric (TE) of a two-dimension photonic crystal (PC) with triangular lattice. The aim of this work is to design a filter with maximum spectral response close to the frequency 1.55 μm. To achieve this frequency, selective filters PC are formed by combination of three waveguides W 1 K A wherein the air holes have of different normalized radii respectively r 1 /a=0.44, r 2 /a=0.288 and r /a= 0.3292 (a: is the periodicity of the lattice with value 0.48 μm). Best response is obtained when we insert three small cylindrical cavities (with normalized radius of 0.17) between the two half-planes of photonic crystal strong lateral confinement.
The Indices of Refraction of Molecular-Beam Epitaxy–Grown BexZn1–xTe Ternary ...Oleg Maksimov
This document discusses a study that uses a combination of prism-coupling, reflectivity, and ellipsometric techniques to determine the indices of refraction (n) of molecular-beam epitaxy grown BexZn1-xTe thin films. Initially, prism-coupling measurements were used to obtain discrete n values and film thicknesses at specific wavelengths. Reflectivity data was then analyzed using the prism-coupling results to determine n dispersion below the bandgap. Ellipsometry was finally used to model n dispersion both below and above the bandgap, guided by the prior thickness and below-bandgap n data from the other techniques. The combination of these three methods allowed for accurate determination of n over a wide wavelength
Field Effect Transistors Based on Composite Films of poly (4 vinyl phenol) wi...theijes
In order to adjust the characteristic of pentacene thin film transistor we modified the dielectric properties of the gate insulator: the poly(4-vinylphenol) (PVP). PVP is an organic polymer with a low dielectric constant, limiting the performance of organic thin film transistor. To increase the dielectric constant of PVP controlled amount of ZnO nanoparticles have been homogeneously dispersed in the dielectric layer. The effect of the concentration of ZnO on the relative permittivity of PVP is measured using impedance spectroscopy it has been demonstrated that the permittivity increase (from 3.6 to 5.5), with no percolation phenomenon even at concentration of 50 vol%. The performance of the OTFT in terms of charge carrier mobility, threshold voltage and linkage current is evaluated. It results in a dramatic increase in both the field effect mobility and the linkage current by a factor of 10. It has been demonstrated that the threshold voltage can be adjusted it shifts from 8 to 0 when the volume concentration of ZnO varied from 0 to 50 vol%.
Study on momentum density in magnetic semiconductor MnTe by positron annihila...IJASCSE
This 3-sentence summary provides the key information from the document:
The document presents a study on calculating momentum density in the magnetic semiconductor MnTe using positron annihilation. Pseudopotential band structure calculations were used to derive electron and positron wave functions in the independent particle model. Electron-positron momentum densities were then calculated for specific planes in MnTe and the results were used to analyze positron effects in the material.
E = g lk+ 2
+ − − +
r m 0 m 0 4 ε 0 h ( ε 0 2 e 0 m 0
8 em hm πεr 2 2ε ) m m hm
Brus, L. E. J. Phys. Chem. 1986, 90, 2555
Semiconductor quantum dots are nanocrystals made of semiconductor materials such as CdSe, ZnSe, ZnS, and ZnO. They exhibit size-dependent optical and electronic properties due to
The document investigates the physical aging of carbon nanotube/PEDOT:PSS nanocomposite thin films with different multi-walled carbon nanotube (MWCNT) concentrations using electrochemical impedance spectroscopy. The key findings are:
1) The aging rate and change in electrical resistance decreases with increasing MWCNT concentration, from 21.2% change for pure PEDOT:PSS to 6.8% change at 0.1 wt.% MWCNT.
2) MWCNTs restrict the mobility of polymer chains near the MWCNT/PEDOT:PSS interface, reducing the aging rate.
3) An equivalent circuit model with tunneling resistance and capacitance components fits the imped
This document summarizes research on the synthesis and characterization of superparamagnetic MgFe2O4 nanoparticles. Key points:
- MgFe2O4 nanoparticles were synthesized via a coprecipitation method and heat treatment.
- Magnetic measurements and neutron diffraction showed the nanoparticles exhibited superparamagnetic behavior, with ferrimagnetic ordering observed via neutron diffraction.
- Mössbauer spectroscopy studies correlated the superparamagnetic relaxation time of the nanoparticles with particle size and temperature, consistent with Neel theory.
The document summarizes a study that used a scanning Kelvin probe to characterize the surface modification of indium tin oxide (ITO) substrates with photopatternable silane adlayers. A photoreactive silane molecule containing an o-nitrobenzyl group was used to form self-assembled monolayers on ITO. UV light through a photomask was used to selectively remove regions of the silane layer, and changes in surface potential were detected using contact potential difference measurements from the scanning Kelvin probe. Additional characterization techniques including X-ray photoelectron spectroscopy and contact angle measurements were also used to analyze the modified surfaces.
The document describes a laser indirect exposure method for treating nanomaterials. The method involves dipping powder materials in a transparent plastic to allow laser beams to pass through without being absorbed by the plastic. This indirectly exposes the powder to laser irradiation, which improves the mechanical properties of the materials. After exposure, an organic solvent is used to separate the treated nanomaterials from the dissolved plastic. Testing showed that laser treatment led to changes in Raman spectra and increased hardness of the treated materials. The method improves properties through laser energy absorption without causing economic losses or pollution.
To analyze a flame retardant nanocomposite, parameters such as heat release rate, carbon monoxide production, and smoke production should be considered by comparing materials with and without nanocomposites. Transmission electron microscopy, X-ray diffractometry, and nuclear magnetic resonance could be used to characterize the nanocomposites. Transmission electron microscopy provides information on particle size, distribution, and morphology while X-ray diffractometry indicates structure and interactions between layers. Nuclear magnetic resonance analyzes polymer-filler interfaces and restricted chain motions at the interface.
Enhanced Exchange Pinning Field For Fe Mn Spin Valvesguestc57e7ed
This document discusses enhanced exchange pinning fields observed in spin-valve structures with ultra-thin magnetic pinned layers and FeMn antiferromagnetic layers. Spin-valves using CoNiFe/Cu, NiFe/Cu, and CoFe/Cu multilayer systems were investigated. Those with ultra-thin pinned layers of approximately 0.5 nm exhibited high pinning fields of 800-900 Oe for CoNiFe/Cu and CoFe/Cu, and around 500 Oe for NiFe/Cu. Enhanced pinning fields were inversely related to pinned layer thickness. Giant magnetoresistance was also measured, decreasing from 3-4% to less than 2% for pinned layers below 0.8 nm
Electromagnetic studies on nano sized magnesium ferriteIAEME Publication
The document summarizes research on the electromagnetic properties of nano-sized magnesium ferrite synthesized using microwave techniques. Key findings include:
1) Magnetic properties were measured using VSM which showed the material has a high coercivity of 785.12 Oe, classifying it as a hard magnetic material.
2) Dielectric measurements found the ac conductivity and dielectric constant decreased with increasing frequency. Both increased with temperature initially before decreasing.
3) The dielectric loss showed expected dispersion behavior, decreasing with frequency and generally increasing with temperature.
4) A high quality factor of 150 was obtained, higher than for bulk ferrites, indicating potential applications in microwave devices.
Electromagnetic studies on nano sized magnesium ferriteIAEME Publication
The document summarizes research on the electromagnetic properties of nano-sized magnesium ferrite synthesized using microwave techniques. Key findings include:
1) Magnetic properties were measured using VSM which showed the material has a high coercivity of 785.12 Oe, classifying it as a hard magnetic material.
2) Dielectric measurements found the ac conductivity and dielectric constant decreased with increasing frequency. Both increased with temperature initially before decreasing.
3) The dielectric loss showed expected dispersion behavior, decreasing with frequency and generally increasing with temperature.
4) A high quality factor of 150 was obtained, higher than for bulk ferrites, indicating potential applications in microwave devices.
Structural and Optical properties of Multiwalled Carbon Nanotubes Modified by...TELKOMNIKA JOURNAL
Structure, chemical, and physical properties of Multiwalled Carbon Nanotubes (MWCNTs) after
modification by dielectric barrier discharge (DBD) at atmospheric pressure is investigated using
Transmission Electron Microscopy (TEM), Raman and Uv-vis-NIR spectroscopy. Effects of plasma
treatment time on MWCNTs are analyzed. TEM result shows that during the short period of plasma
treatment time of 5 minutes, the tube surface experienced a few damages. With increase in plasma
treatment time, the tube surface is damaged to a certain extent. Intensity ratio, ID/IG through Raman
analysis shows a good agreement with TEM. The values of ID/IG of the modified MWCNTs are larger than
those of pristine MWCNTs. An increase of ID/IG indicates that considerable defects are produced on the
surfaces of MWCNTs. The treated MWCNTs has energy band gap compared to zero band gap of
untreated MWCNTs. It is believed that the defect site of MWCNTs can modify the electronics properties of
MWCNTs from being metallic to semiconducting structure, which is applicable for almost all electronics
device applications.
Greener cum chemical synthesis and characterization of Mg doped ZnS nanoparti...IJERA Editor
In the present investigations, high-quality Mg doped ZnS nanoparticles were synthesized by Greener cum
chemical process with the assistance of polyvinyl pyrrolidone (PVP) with two different Mg concentrations.
Doping of Mg metal in nanoparticles were found to be a good technique for tuning the band gap of ZnS
nanoparticles. Simultaneously, Mg doping also inhibited the growth of particle size and it decreased from 33.2
nm to 18.3 nm with the increase in doping concentration from 0% to 5%. Band gap was found to rise from 3.12
eV to 3.38 eV and photoluminescence studies exposed that visible Photoluminescence (PL) emission was
improved with doping concentration. The nanoparticles have been characterized by Field Emission Scanning
Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy,
Ultra Violet visible (UV–vis) spectroscopy, and Energy Dispersive X-ray Analysis (EDAX).
Enhanced Exchange Pinning Field For Fe Mn Spin Valvesguestc57e7ed
This document discusses enhanced exchange pinning fields observed in spin-valve structures with ultra-thin magnetic pinned layers and FeMn antiferromagnetic layers. Three material systems - CoNiFe/Cu, NiFe/Cu, and CoFe/Cu - were investigated. Spin-valves with pinned layers as thin as 0.5 nm exhibited exchange pinning fields as high as 800-900 Oe for CoNiFe/Cu and CoFe/Cu multilayers, while NiFe/Cu multilayers achieved a pinning field of around 500 Oe. Using ultra-thin pinned layers reduced demagnetizing effects and improved spin-valve performance in terms of linearity.
The document summarizes a study of the dielectric properties of nano-crystalline Mn-Zn ferrites. Samples of ZnxMn1-xFe2O4 where x ranges from 0.2 to 0.8 were synthesized using a solid-state route and characterized. The ac conductivity σ, dielectric constant ε', dielectric loss ε'', and loss tangent tan δ were measured from 100 Hz to 20 MHz. ε' and ε'' decreased with increasing frequency. σ was nearly frequency independent below 1 MHz and increased sharply above. The maximum dielectric constant and conductivity occurred for x=0.2, attributed to space charge polarization. The conduction mechanism was explained by electron hopping between Fe2+ and Fe
This document summarizes the presentation given by Kanupriya on the properties of nanomaterials. It discusses how the properties of materials change from bulk to nano size, including becoming transparent, stronger, and more chemically reactive. It specifically examines how optical, magnetic, and chemical properties are affected by the nano size. Optical properties depend on quantum confinement and surface plasmon resonance. Magnetic properties transition from ferromagnetic to superparamagnetic. Chemical reactivity increases due to more surface atoms. A variety of nanomaterials like quantum dots and metallic nanoparticles were highlighted.
This document discusses the application of a ferromagnetic composite material in tunable microwave devices. Specifically:
- The composite material consists of ferromagnetic and insulating thin film layers that exhibit tunable intrinsic impedance when a DC magnetic field is applied.
- Several microwave devices were demonstrated using this composite material, including a tunable bandstop filter with 50% tunability, phase shifters with figures of merit of 35 deg/dB around 3 GHz and 7.8 deg/dB in the X band, and a magnetic switch with over 25 dB isolation and less than 1 dB insertion loss.
- The tunable behavior results from changes in the ferromagnetic resonance frequency of the composite material under an applied magnetic field, which
This document describes magnetic tweezers, which are instruments that use magnetic fields to manipulate biomolecules. Magnetic tweezers typically exert piconewton forces on superparamagnetic beads attached to molecules like DNA or proteins to study their mechanical properties. They consist of magnets above a microscope that tracks bead position. Magnetic tweezers allow studying properties of single molecules and complexes by twisting or stretching molecules between a surface and bead. They have high resolution but low throughput. Recent advances aim to improve fields and resolution for diverse single molecule applications.
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.
Modulus spectroscopy study on Ferroelectric Lithium and Titanium modified Lea...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a Selective Filter based on 2D Photonic Crystals Materials IJECEIAES
Two dimensional finite differences temporal domain (2D-FDTD) numerical simulations are performed in cartesian coordinate system to determine the dispersion diagrams of transverse electric (TE) of a two-dimension photonic crystal (PC) with triangular lattice. The aim of this work is to design a filter with maximum spectral response close to the frequency 1.55 μm. To achieve this frequency, selective filters PC are formed by combination of three waveguides W 1 K A wherein the air holes have of different normalized radii respectively r 1 /a=0.44, r 2 /a=0.288 and r /a= 0.3292 (a: is the periodicity of the lattice with value 0.48 μm). Best response is obtained when we insert three small cylindrical cavities (with normalized radius of 0.17) between the two half-planes of photonic crystal strong lateral confinement.
The Indices of Refraction of Molecular-Beam Epitaxy–Grown BexZn1–xTe Ternary ...Oleg Maksimov
This document discusses a study that uses a combination of prism-coupling, reflectivity, and ellipsometric techniques to determine the indices of refraction (n) of molecular-beam epitaxy grown BexZn1-xTe thin films. Initially, prism-coupling measurements were used to obtain discrete n values and film thicknesses at specific wavelengths. Reflectivity data was then analyzed using the prism-coupling results to determine n dispersion below the bandgap. Ellipsometry was finally used to model n dispersion both below and above the bandgap, guided by the prior thickness and below-bandgap n data from the other techniques. The combination of these three methods allowed for accurate determination of n over a wide wavelength
Field Effect Transistors Based on Composite Films of poly (4 vinyl phenol) wi...theijes
In order to adjust the characteristic of pentacene thin film transistor we modified the dielectric properties of the gate insulator: the poly(4-vinylphenol) (PVP). PVP is an organic polymer with a low dielectric constant, limiting the performance of organic thin film transistor. To increase the dielectric constant of PVP controlled amount of ZnO nanoparticles have been homogeneously dispersed in the dielectric layer. The effect of the concentration of ZnO on the relative permittivity of PVP is measured using impedance spectroscopy it has been demonstrated that the permittivity increase (from 3.6 to 5.5), with no percolation phenomenon even at concentration of 50 vol%. The performance of the OTFT in terms of charge carrier mobility, threshold voltage and linkage current is evaluated. It results in a dramatic increase in both the field effect mobility and the linkage current by a factor of 10. It has been demonstrated that the threshold voltage can be adjusted it shifts from 8 to 0 when the volume concentration of ZnO varied from 0 to 50 vol%.
Study on momentum density in magnetic semiconductor MnTe by positron annihila...IJASCSE
This 3-sentence summary provides the key information from the document:
The document presents a study on calculating momentum density in the magnetic semiconductor MnTe using positron annihilation. Pseudopotential band structure calculations were used to derive electron and positron wave functions in the independent particle model. Electron-positron momentum densities were then calculated for specific planes in MnTe and the results were used to analyze positron effects in the material.
E = g lk+ 2
+ − − +
r m 0 m 0 4 ε 0 h ( ε 0 2 e 0 m 0
8 em hm πεr 2 2ε ) m m hm
Brus, L. E. J. Phys. Chem. 1986, 90, 2555
Semiconductor quantum dots are nanocrystals made of semiconductor materials such as CdSe, ZnSe, ZnS, and ZnO. They exhibit size-dependent optical and electronic properties due to
The document investigates the physical aging of carbon nanotube/PEDOT:PSS nanocomposite thin films with different multi-walled carbon nanotube (MWCNT) concentrations using electrochemical impedance spectroscopy. The key findings are:
1) The aging rate and change in electrical resistance decreases with increasing MWCNT concentration, from 21.2% change for pure PEDOT:PSS to 6.8% change at 0.1 wt.% MWCNT.
2) MWCNTs restrict the mobility of polymer chains near the MWCNT/PEDOT:PSS interface, reducing the aging rate.
3) An equivalent circuit model with tunneling resistance and capacitance components fits the imped
This document summarizes research on the synthesis and characterization of superparamagnetic MgFe2O4 nanoparticles. Key points:
- MgFe2O4 nanoparticles were synthesized via a coprecipitation method and heat treatment.
- Magnetic measurements and neutron diffraction showed the nanoparticles exhibited superparamagnetic behavior, with ferrimagnetic ordering observed via neutron diffraction.
- Mössbauer spectroscopy studies correlated the superparamagnetic relaxation time of the nanoparticles with particle size and temperature, consistent with Neel theory.
The document summarizes a study that used a scanning Kelvin probe to characterize the surface modification of indium tin oxide (ITO) substrates with photopatternable silane adlayers. A photoreactive silane molecule containing an o-nitrobenzyl group was used to form self-assembled monolayers on ITO. UV light through a photomask was used to selectively remove regions of the silane layer, and changes in surface potential were detected using contact potential difference measurements from the scanning Kelvin probe. Additional characterization techniques including X-ray photoelectron spectroscopy and contact angle measurements were also used to analyze the modified surfaces.
The document describes a laser indirect exposure method for treating nanomaterials. The method involves dipping powder materials in a transparent plastic to allow laser beams to pass through without being absorbed by the plastic. This indirectly exposes the powder to laser irradiation, which improves the mechanical properties of the materials. After exposure, an organic solvent is used to separate the treated nanomaterials from the dissolved plastic. Testing showed that laser treatment led to changes in Raman spectra and increased hardness of the treated materials. The method improves properties through laser energy absorption without causing economic losses or pollution.
To analyze a flame retardant nanocomposite, parameters such as heat release rate, carbon monoxide production, and smoke production should be considered by comparing materials with and without nanocomposites. Transmission electron microscopy, X-ray diffractometry, and nuclear magnetic resonance could be used to characterize the nanocomposites. Transmission electron microscopy provides information on particle size, distribution, and morphology while X-ray diffractometry indicates structure and interactions between layers. Nuclear magnetic resonance analyzes polymer-filler interfaces and restricted chain motions at the interface.
Enhanced Exchange Pinning Field For Fe Mn Spin Valvesguestc57e7ed
This document discusses enhanced exchange pinning fields observed in spin-valve structures with ultra-thin magnetic pinned layers and FeMn antiferromagnetic layers. Spin-valves using CoNiFe/Cu, NiFe/Cu, and CoFe/Cu multilayer systems were investigated. Those with ultra-thin pinned layers of approximately 0.5 nm exhibited high pinning fields of 800-900 Oe for CoNiFe/Cu and CoFe/Cu, and around 500 Oe for NiFe/Cu. Enhanced pinning fields were inversely related to pinned layer thickness. Giant magnetoresistance was also measured, decreasing from 3-4% to less than 2% for pinned layers below 0.8 nm
Electromagnetic studies on nano sized magnesium ferriteIAEME Publication
The document summarizes research on the electromagnetic properties of nano-sized magnesium ferrite synthesized using microwave techniques. Key findings include:
1) Magnetic properties were measured using VSM which showed the material has a high coercivity of 785.12 Oe, classifying it as a hard magnetic material.
2) Dielectric measurements found the ac conductivity and dielectric constant decreased with increasing frequency. Both increased with temperature initially before decreasing.
3) The dielectric loss showed expected dispersion behavior, decreasing with frequency and generally increasing with temperature.
4) A high quality factor of 150 was obtained, higher than for bulk ferrites, indicating potential applications in microwave devices.
Electromagnetic studies on nano sized magnesium ferriteIAEME Publication
The document summarizes research on the electromagnetic properties of nano-sized magnesium ferrite synthesized using microwave techniques. Key findings include:
1) Magnetic properties were measured using VSM which showed the material has a high coercivity of 785.12 Oe, classifying it as a hard magnetic material.
2) Dielectric measurements found the ac conductivity and dielectric constant decreased with increasing frequency. Both increased with temperature initially before decreasing.
3) The dielectric loss showed expected dispersion behavior, decreasing with frequency and generally increasing with temperature.
4) A high quality factor of 150 was obtained, higher than for bulk ferrites, indicating potential applications in microwave devices.
Performance comparison of selection nanoparticles for insulation of three cor...IJECEIAES
This paper presents an investigation on the enhancement of electrical insulations of power cables materials using a new multi-nanoparticles technique. It has been studied the effect of adding specified types and concentrations of nanoparticles to polymeric materials such as PVC for controlling on electric and dielectric performance. Prediction of effective dielectric constant has been done for the new nanocomposites based on Interphase Power Law (IPL) model. The multi-nanoparticles technique has been succeeded for enhancing electric and dielectric performance of power cables insulation compared with adding individual nanoparticles. Finally, it has been investigated on electric field distribution in the new proposed modern insulations for three-phase core belted power cables. This research has focused on studying development of PVC nanocomposite materials performance with electric field distribution superior to the unfilled matrix, and has stressed particularly the effect of filler volume fraction on the electric field distribution.
Reconfigurable Metamaterial Structure at Millimeter Wave Frequency Range IJECEIAES
In this paper, reconfigurable metamaterial structure at millimeter wave frequency range was designed and simulated for a future fifth generation (5G) mobile-phone beam switching applications. The new proposed structure was composed of a bridge-shaped resonator (BSR) in the front face and strip line at the back face of the unit cell which operates at 28GHz. First, nonreconfigurable low loss BSR unit cell was designed and subsequently, the reconfigurability was achieved using four switches formed in the gaps of the structure. The proposed structure achieves the lowest loss and almost full transmission among its counterparts by -0.06dB (0.99 in linear scale). To demonstrate the reconfigurability of the metamaterial, the reflection and transmission coefficients and real parts of the effective refractive index at each reconfigured frequency were studied and investigated. Simulation results showed that a high transmission and reflection peaks occur at each resonance frequency according to change the state of the switches.
This document provides an overview of the Institute of Nanoscience and its research activities related to semiconductor nanostructures and their applications. The institute has over 250 researchers studying the fundamental properties and manipulation of nanoscale systems through synthesis, fabrication, experimental and theoretical studies of nanostructures and devices. Key areas of research include semiconductor nanowires for applications in electronics, optoelectronics and spintronics. Heterostructured nanowires of InAs, InSb and InP are investigated for high mobility transistors and terahertz detectors. Strain-driven self-assembly is used to create 3D nanostructures for applications in sensing, energy harvesting and photonics.
Electrical transport properties of nanocrystalline and bulk nickel.pdfProximaCentauri15
In this work, the comparative study on the electrical transport properties of nanocrystalline nickel
ferrite (NiFe2O4) and its bulk counterpart has been carried out in detail by using complex impedance
spectroscopy in a wide range of frequencies (100 Hz–1 MHz) and temperatures (40 °C–320 °C). The
dispersive nature of the dielectric constant and loss factor is explained by the Maxwell-Wagner model
and Koop’s phenomenological theory. The value of the dielectric constant for nanocrystalline nickel
ferrite is found to be more as compared to its bulk counterpart. The frequency variation dielectric
permittivity is well fitted with the modified Debye formula, which suggests the presence of multiple
relaxation processes. The temperature dependent ac conductivity follows Jonscher’s universal power
law and reveals the presence of multiple transport mechanisms from small polaron hopping (SPH) to
correlated barrier hopping (CBH) mechanism near 200 °C. The estimated values of Mott parameters
are found to be satisfactory. Thermally activated relaxation phenomena have been confirmed by
scaling curves of imaginary impedance (Z) andmodulus (M). The comparison between the Z and
M spectra indicates that both long-range and short-rangemovement of charge carriers contribute to
dielectric relaxation with short-range charge carriers predominating at low temperatures while longrange
charge carriers are dominating at high temperatures. Analysis of the semicircular arcs of Nyquist
plot indicates the presence of grain boundary contribution to the electrical conduction process for the
nanocrystalline sample at high temperatures. The non-Debye type of relaxation has been examined by
stretching exponential factor (β) which has been estimated by fitting the modifiedKWW
(Kohlrausch-Williams-Watts) equation to the imaginary electric modulus curve. The value of β is
found to be strongly temperature dependent and its value for the nanocrystalline sample is less than
that of the bulk system which is explained on the basis of dipole-dipole interaction.
This document discusses the study of optical characteristics of nano-antennas. It begins by introducing metallic optical nano-antennas and how their properties depend on geometry and materials. Nano-antennas have potential applications in nanophotonics by confining electromagnetic waves at metal-dielectric interfaces at scales smaller than the light wavelength. Different types of nano-antennas are presented, including dipole antennas and spiral antennas. The document discusses several key optical properties of nano-antennas including their polarization sensitivity, directional sensitivity, and applications in areas like plasmonic sensing and biochemical detection. In conclusions, nano-antennas represent an area of light detection where both technological and fundamental problems need to be addressed through further research.
Electrical properties of Ni0.4Mg0.6Fe2O4 ferritesIJERA Editor
Ni0.4Mg0.6Fe2O4 Ceramic samples were prepared by conventional double sintering approach and sintered at 1300oC/4 h. These ferrites are further characterized using X-ray diffractometer. The diffraction study reveals that the present compound shows perfect single phase cubic spinel structure. In addition, the behavior of distinct electrical properties such as dielectric constant (ε'), dielectric loss (ε") and ac-conductivity (ζac) as a function frequency as well as temperature is analyzed using the LCR controller.
Analysis and simulations of optimal geometry shapes of the 4 and 9 nano hole ...IJECEIAES
The possibility to limit and manipulate photons at nanometer scales attracted a lot of interest for exciting applications from subwavelength in laser, biosensors, biomedical and optoelectronics devices, the sensor optical properties, however; are complex due to two resonances through propagating and localized surface plasmons. The optical properties of surface plasmons (SPs) at the resonant wavelength is depending on the geometrical nanostructure of materials. In this article, we used different geometry of nanoholes array, 4 and 9 nanoholes array in a metallic film gold nanoparticle with different thickness (20,50,100) nm on SiO2 substrate with refractive index 1.46, we designed two different geometries; 4- holes: hole radius r1=200 nm, period p1=600 nm; and 9- holes: r2=100 nm, period p2=300 nm. Transmission and reflection spectrum have been calculated and simulated by FDTD Lumerical program. From results are observed the effect of thickness is interesting, transmission is increased at (t=20nm) for two arrays. Furthermore, the number of hole and its area has an influence on optical transmission and other parameters (E, H, Ref) which are characteristics of design of metallic nanostructure. We can see that there is a peak value of the wavelength at 519 nm approximately to 73% strong light transmission with 4-NHA in the other hand wavelength of 519 nm transmission is 45% with 9-NHA. strong light transmission is hopeful for many applications (biomedical devices, nanoantennas and laser optical fiber).
Optical and Impedance Spectroscopy Study of ZnS NanoparticlesIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
This document summarizes research characterizing ohmic and Schottky contacts on single ZnO nanowires. Current-voltage and Kelvin probe force microscopy measurements were performed on nanowires with different contact geometries. Nanowires with linear I-V behavior exhibited ohmic contacts and a uniform potential along the wire. Nanowires with non-linear I-V curves exhibited Schottky behavior at one contact, shown by a sharp potential drop. Schottky behavior was more likely for thinner nanowires where the depletion region could extend across the entire wire width under the contact.
During the last decades a large effort has been invested in the development of a new
discipline devoted to benefit from optical excitations in materials where metals are
key element (Plasmonics). We will make an introduction on this topic below, but let’s
anticipate that two application areas are sensing and information technologies.
The following height extended abstracts, presented during the one-day NANOMAGMA
Symposium (Bilbao, Spain – April 13, 2011 reflects some of the latest developments on magneto-plasmonics.
In 2010 and 2011, the nanoICT project (EU/ICT/FET Coordination Action) launched
two calls for exchange visits for PhD students with the following main objectives: 1.
To perform joint work or to be trained in the leading European industrial and academic research institutions; 2. To enhance long-term collaborations within the ERA; 3. To
generate high-skilled personnel and to facilitate technology transfer;
The first outcome report was published in the issue 22 (August 2011) and this edition
contains four new articles providing insights in relevant fi elds for nanoICT.
We would like to thank all the authors who contributed to this issue as well as the European Commission for the financial support (projects nanoICT No. 216165 and NANOMAGMA No. FP7-214107-2).
Dr. Antonio Correia Editor - Phantoms Foundation
This document summarizes the design, fabrication, and testing of a microfluidic chip prototype for manipulating particles using dielectrophoresis (DEP). Finite element modeling was used to simulate the electric field distributions around quadrupole and comb electrode geometries. A prototype was fabricated containing these electrode designs in two separate microchannels. Silica microspheres were successfully manipulated within the chip using positive and negative DEP sequences, concentrating particles in the electrode areas. Testing demonstrated the potential of this technique for manipulating and separating microparticles in integrated microfluidic devices.
Device simulation of perovskite solar cells with molybdenum disulfide as acti...journalBEEI
Organo-halide Perovskite Solar Cells (PSC) have been reported to achieve remarkably high power conversion efficiency (PCE). A thorough understanding of the role of each component in solar cells and their effect as a whole is still required for further improvement in PCE. In this paper, the effect of Molybdenum Disulfide (MoS2) in PSC with mesoporous structure configuration was analyzed using Solar Cell Capacitance Simulator (SCAPS). With the MoS2 layer which having two-fold function, acting as a protective layer, by preventing the formation of shunt contacts between perovskite and Au electrode, and as a hole transport material (HTM) from the perovskite to the Spiro-OMETAD. As simulated, PSC demonstrates a PCE, ŋ of 13.1%, along with stability compared to typical structure of PSC without MoS2 (Δ ŋ/ŋ=-9% vs. Δ ŋ/ŋ=-6%). The results pave the way towards the implementation of MoS2 as a material able to boost shelf life which very useful for new material choice and optimization of HTMs
10.1016-j.mssp.2015.01.037-Electrochemical investigation of graphene_nanoporo...Mahdi Robat Sarpoushi
This study investigated the effect of mixing graphene nanosheets and nanoporous carbon black on the surface morphology and electrochemical performance of electrodes prepared for supercapacitors. Electrodes containing 80% nanoporous carbon black, 10% graphene nanosheets, and 10% PTFE binder showed the highest specific capacitance of 10.22 F/g. The addition of nanoporous carbon black increased the proportion of outer charge stored on the electrode relative to the total charge stored, indicating higher current response and voltage reversal at the end potentials. Scanning electron microscopy images showed that adding nanoporous carbon black particles arranged the graphene nanosheets in different directions, increasing the specific surface area and changing diffusion characteristics to improve capacitance and reversibility
The effect of magnetic field direction on thermoelectric and thermomagnetic c...Muhammid Al-Baghdadi
This document investigates the effect of magnetic field direction on thermoelectric and thermomagnetic coefficients of undoped single crystalline InSb at room temperature. It describes how samples of InSb were tested under varying magnetic fields and temperature gradients to measure the Seebeck and Nernst coefficients. The results showed that the Seebeck coefficient depended only on the temperature gradient, while the Nernst coefficient depended on both the temperature gradient and magnetic field. However, the values of the thermoelectric and thermomagnetic coefficients were found to be independent of the direction of the applied magnetic field with respect to the InSb sample surface.
This document summarizes the electronic, thermal, and mechanical properties of carbon nanotubes. It discusses their cylindrical structure and how this leads to novel properties. Carbon nanotubes have extraordinary strength and stiffness, with some having a tensile strength over 60 times greater than steel. They are also highly thermally conductive and can transport heat more efficiently than copper. Carbon nanotubes can be metallic or semiconducting depending on their structure, and this quantum confinement of electrons leads to unique electrical properties including ballistic conduction. Their structure also results in sharp optical transitions that can be used to identify different nanotube types.
This document summarizes a study on the electrical properties of electrodeposited zinc-copper-telluride (ZnCuTe) ternary nanowires embedded in polycarbonate membranes. Scanning electron microscopy confirmed the formation of uniform diameter nanowires equal to the pore diameters of 200nm, 100nm, and 50nm templates used. Electrical measurements found the nanowires exhibited linear and ohmic characteristics. Larger diameter nanowires showed higher electron transport than smaller ones. Temperature-dependent measurements from 308K-423K revealed electrical conductivity increased with temperature and decreased with smaller nanowire size, with ZnCuTe nanowires exhibiting negative temperature coefficients of resistance.
Photonic band gap (PBG) materials are artificially created materials that prevent the propagation of electromagnetic waves within a forbidden bandgap. PBG materials find various applications including EMI shielding, miniaturization of photonic devices, and magnetic field sensing. Photonic crystal fibers use the bandgap effect to guide light and have uses in telecommunications, sensing, and medicine.
Similar to Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt multilayers nanowires (20)
An Examination of Effectuation Dimension as Financing Practice of Small and M...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Does Goods and Services Tax (GST) Leads to Indian Economic Development?iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Childhood Factors that influence success in later lifeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Emotional Intelligence and Work Performance Relationship: A Study on Sales Pe...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer’s Acceptance of Internet Banking in Dubaiiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study of Employee Satisfaction relating to Job Security & Working Hours amo...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumer Perspectives on Brand Preference: A Choice Based Model Approachiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Student`S Approach towards Social Network Sitesiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Broadcast Management in Nigeria: The systems approach as an imperativeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study on Retailer’s Perception on Soya Products with Special Reference to T...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study Factors Influence on Organisation Citizenship Behaviour in Corporate ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumers’ Behaviour on Sony Xperia: A Case Study on Bangladeshiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a Balanced Scorecard on Nonprofit Organizations (Study on Yayasan P...iosrjce
1. The document describes a study that designed a balanced scorecard for a nonprofit organization called Yayasan Pembinaan dan Kesembuhan Batin (YPKB) in Malang, Indonesia.
2. The balanced scorecard translated YPKB's vision and mission into strategic objectives across four perspectives: financial, customer, internal processes, and learning and growth.
3. Key strategic objectives included donation growth, budget effectiveness, customer satisfaction, reputation, service quality, innovation, and employee development. Customers perspective had the highest weighting, suggesting a focus on public service over financial growth.
Public Sector Reforms and Outsourcing Services in Nigeria: An Empirical Evalu...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Media Innovations and its Impact on Brand awareness & Considerationiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer experience in supermarkets and hypermarkets – A comparative studyiosrjce
- The document examines customer experience in supermarkets and hypermarkets in India through a survey of 418 customers.
- It finds that in supermarkets, previous experience, atmosphere, price, social environment and experience in other channels most influence customer experience, while in hypermarkets, previous experience, product assortment, social environment and experience in other channels are most influential.
- The study provides insights for retailers on key determinants of customer experience in each format to help them improve strategies and competitive positioning.
Social Media and Small Businesses: A Combinational Strategic Approach under t...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Secretarial Performance and the Gender Question (A Study of Selected Tertiary...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Implementation of Quality Management principles at Zimbabwe Open University (...iosrjce
This document discusses the implementation of quality management principles at Zimbabwe Open University's Matabeleland North Regional Centre. It begins with background information on ZOU and the importance of quality management in open and distance learning institutions. The study aimed to determine if quality management and its principles were being implemented at the regional centre. Key findings included that the centre prioritized customer focus and staff involvement. Decisions were made based on data analysis. The regional centre implemented a quality system informed by its policy documents. The document recommends ensuring staffing levels match needs and providing sufficient resources to the regional centre.
Organizational Conflicts Management In Selected Organizaions In Lagos State, ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...Travis Hills MN
By harnessing the power of High Flux Vacuum Membrane Distillation, Travis Hills from MN envisions a future where clean and safe drinking water is accessible to all, regardless of geographical location or economic status.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Microbial interaction
Microorganisms interacts with each other and can be physically associated with another organisms in a variety of ways.
One organism can be located on the surface of another organism as an ectobiont or located within another organism as endobiont.
Microbial interaction may be positive such as mutualism, proto-cooperation, commensalism or may be negative such as parasitism, predation or competition
Types of microbial interaction
Positive interaction: mutualism, proto-cooperation, commensalism
Negative interaction: Ammensalism (antagonism), parasitism, predation, competition
I. Mutualism:
It is defined as the relationship in which each organism in interaction gets benefits from association. It is an obligatory relationship in which mutualist and host are metabolically dependent on each other.
Mutualistic relationship is very specific where one member of association cannot be replaced by another species.
Mutualism require close physical contact between interacting organisms.
Relationship of mutualism allows organisms to exist in habitat that could not occupied by either species alone.
Mutualistic relationship between organisms allows them to act as a single organism.
Examples of mutualism:
i. Lichens:
Lichens are excellent example of mutualism.
They are the association of specific fungi and certain genus of algae. In lichen, fungal partner is called mycobiont and algal partner is called
II. Syntrophism:
It is an association in which the growth of one organism either depends on or improved by the substrate provided by another organism.
In syntrophism both organism in association gets benefits.
Compound A
Utilized by population 1
Compound B
Utilized by population 2
Compound C
utilized by both Population 1+2
Products
In this theoretical example of syntrophism, population 1 is able to utilize and metabolize compound A, forming compound B but cannot metabolize beyond compound B without co-operation of population 2. Population 2is unable to utilize compound A but it can metabolize compound B forming compound C. Then both population 1 and 2 are able to carry out metabolic reaction which leads to formation of end product that neither population could produce alone.
Examples of syntrophism:
i. Methanogenic ecosystem in sludge digester
Methane produced by methanogenic bacteria depends upon interspecies hydrogen transfer by other fermentative bacteria.
Anaerobic fermentative bacteria generate CO2 and H2 utilizing carbohydrates which is then utilized by methanogenic bacteria (Methanobacter) to produce methane.
ii. Lactobacillus arobinosus and Enterococcus faecalis:
In the minimal media, Lactobacillus arobinosus and Enterococcus faecalis are able to grow together but not alone.
The synergistic relationship between E. faecalis and L. arobinosus occurs in which E. faecalis require folic acid
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
CLASS 12th CHEMISTRY SOLID STATE ppt (Animated)eitps1506
Description:
Dive into the fascinating realm of solid-state physics with our meticulously crafted online PowerPoint presentation. This immersive educational resource offers a comprehensive exploration of the fundamental concepts, theories, and applications within the realm of solid-state physics.
From crystalline structures to semiconductor devices, this presentation delves into the intricate principles governing the behavior of solids, providing clear explanations and illustrative examples to enhance understanding. Whether you're a student delving into the subject for the first time or a seasoned researcher seeking to deepen your knowledge, our presentation offers valuable insights and in-depth analyses to cater to various levels of expertise.
Key topics covered include:
Crystal Structures: Unravel the mysteries of crystalline arrangements and their significance in determining material properties.
Band Theory: Explore the electronic band structure of solids and understand how it influences their conductive properties.
Semiconductor Physics: Delve into the behavior of semiconductors, including doping, carrier transport, and device applications.
Magnetic Properties: Investigate the magnetic behavior of solids, including ferromagnetism, antiferromagnetism, and ferrimagnetism.
Optical Properties: Examine the interaction of light with solids, including absorption, reflection, and transmission phenomena.
With visually engaging slides, informative content, and interactive elements, our online PowerPoint presentation serves as a valuable resource for students, educators, and enthusiasts alike, facilitating a deeper understanding of the captivating world of solid-state physics. Explore the intricacies of solid-state materials and unlock the secrets behind their remarkable properties with our comprehensive presentation.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
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. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
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Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
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Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...
Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt multilayers nanowires
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861.Volume 7, Issue 2 Ver. I (Mar. - Apr. 2015), PP 09-15
www.iosrjournals.org
DOI: 10.9790/4861-07210915 www.iosrjournals.org 9 | Page
Site-specific measurement of the giant magnetoresistance (GMR)
of individual NiFe/Pt multilayers nanowires
Mohamed Elawayeb1*
, Kevin J. Briston2
, Yong Peng3
and Beverley J. Inkson2
1
Biomedical Engineering/ College of medical Technology Misurata, Libya
2
Department of Materials Science and Engineering, University of Sheffield, UK
3
Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, School of Physical
and Technology, Lanzhou University 730000, China
Abstract: As devices shrink, there is a requirement to characterize the magnetic properties of individual
inhomogeneous nanosized components. Here the site-specific giant magnetoresistance (GMR) of individual
NiFe/Pt multilayer nanowires has been evaluated in the current perpendicular to plane (CPP) geometry using a
new in-situ method directly inside a scanning electron microscope (SEM). In this method a controlled magnetic
field is produced directly inside the SEM using a custom designed electromagnet. Two nanomanipulators
equipped with sharp tips enable the site-specific measurement of the resistance of individual nanowires in the
gap between the coils as the field is varied. The CPP-GMR measurement of ~70 nm diameter individual NiFe/Pt
multilayer nanowires shows that, at 500 Oe, the nanowires have a magnetoresistance effect of up to 5.8 %
dependant on the nanowire layer thicknesses and magnetic field orientation. This in-situ method of GMR
measurement enables precise nanocharacterisation of magnetoresistance of nanowires as a function of local
nanowire microstructure, geometry, length, and field orientation, whilst concurrently allowing the observation
of any changes to the microstructure.
Keywords: Giant magnetoresistance (GMR), multilayer nanowires, in-situ SEM.
I. Introduction
Nanostructured materials such as nanoparticles, nanorods and nanowires can exhibit novel and
magnetoresistance properties and thus have important technological applications in nanosensors [1,2],
information storage systems [3,4] and electronic devices [5]. Nanostructured magnetic materials can consist of
one or more ferromagnetic elements such as Fe, Ni and Co [6] or a combination of magnetic and nonmagnetic
elements such as Ni/Cu [7] and CoPt/Pt [8]. The magnetoresistance properties of the nanomaterials are affected
by the nanoscale microstructure, geometry and defects of these elements.
In recent years the trend has been for smaller devices making use of inhomogeneous nanocomponents
such as magnetic nanowires as opposed to, for example, thin films. It is important therefore to be able to
characterize nanocomponents individually rather than in groups and with high spatial resolution along a given
inhomogeneous component. Due to technology limitations, however, most magnetoresistance measurements
made on multilayered nanowires over the last decade have been based on an average of multiple nanowires,
contacted while still inside the template used in the manufacturing process, rather than the measurement of
individual nanowires [9,10]. This is due to the difficulties of connecting probe electrodes to a single nanowire.
Measurements are typically performed by making contact on either side of the template, and the numbers of
contacted wires between the contact points are estimated [9,10]. Subsequently, some groups have improved
these methods by reducing the number of wires embedded in a template that are contacted by using a low pore
density template, for example a polymer template (< 109
pores cm−2
) [11], or using a single pore template [12].
Another improved method involves dissolving the template, dispersing the nanowires on a substrate and then
contacting individual nanowires using fixed electrodes attached by e-beam lithography [13].
In this work, we report a new, flexible technique that enables site-specific GMR measurements to be
made on individual nanowires with real-time imaging of the structures under test. This technique makes use of a
novel in-situ electromagnet inside a scanning electron microscope (SEM), and movable electrodes attached to
nanomanipulators. Site-specific GMR measurement has been applied to the characterization of
magnetoresistance of individual NiFe/Pt nanowires. The in-situ method has the advantages that it allows the
magnetoresistance properties of multilayer nanowires to be measured between chosen contact points, at variable
lengths and at variable magnetic field. Measuring nanowires while they are in a template, on the other hand,
means that the length and contact points are fixed. Also, any inhomogeneities in the wires being tested cannot be
directly observed or avoided in the measurement process.
2. Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt ….
DOI: 10.9790/4861-07210915 www.iosrjournals.org 10 | Page
II. Experimental Procedure
The new technique for GMR measurement inside a SEM utilizes an electromagnet made from two
small coils wound around 2 mm diameter pure iron (Fe) rods. Each coil is formed from 350 turns of 0.2 mm
diameter insulated copper wire to create an electromagnet. The two magnetic coils, which act as a source of
controlled magnetic field within the SEM chamber, are mounted in a 30 mm diameter Al base and are separated
by a 2mm gap (Fig. 1(a)). The magnetic field of the coils was calibrated using a Hall probe before nanowires
were positioned in the gap.
Magnetic multi-layered nanowires of different combinations of magnetic and nonmagnetic layer
elements are ideal structures to study the GMR effect as the resistances of nanowires are much larger than the
resistances of equivalent multi-layered thin films. Here, the GMR effect of the magnetic NiFe/Pt multilayer
nanowires was measured in the current perpendicular to plane (CPP) geometry by placing the nanowires
between the coils and connecting to them electrically using the tip electrodes (Fig. 1(b)). The measurements
were made on individual nanowires in magnetic fields up to H = 500 Oe and at different orientations of the
externally applied magnetic field with respect to wire axis (θ = 0°, 90°).
Electrodeposition into anodic aluminium oxide (AAO) nanoporous templates has been utilized to
produce the NiFe/Pt nanowires since nanowires with flexible geometry, chemistry and with high aspect ratio can
be easily grown by this method [14,15]. Nanoporous AAO templates with ~ 70 nm diameter pores were
prepared by a one-step anodization technique using 0.6 M oxalic acid solution and an applied voltage of 40 V
for 180 min with continuous stirring. The multi-layered NiFe/Pt nanowires were fabricated by a three electrode
electrolytic cell at room temperature using a single bath solution containing 90 g/l NiSO4, 13.5 g/l FeSO4, 5 g/l
PtCl4 and 30 g/l H3BO3. The electrodeposition process of the multilayer nanowires was carried out at a constant
voltage of −1.4 V for NiFe layers and −0.4 V for Pt layers. The fabrication techniques of the AAO templates
and NiFe/Pt nanowires are described in a previous paper [16].
The morphology and structure of individual NiFe/Pt nanowires were characterized at the nanoscale
using SEM (JEOL JSM 6500F, Japan) and transmission electron microscopy (TEM) (JEOL JEM-2010F, Japan).
The magnetoresistance of individual NiFe/Pt multilayer nanowires was measured in-situ in a SEM using the in-
situ electromagnet and two Kleindiek MM3A nanomanipulators connected to a Keithley 6487 picoammeter.
Two sharp conductive nichrome probe tips were used in the nanomanipulators as electrodes and were prepared
by electrochemical etching in a solution of 1M NaCl [17].
FIG. 1. (a) Image of the SEM magnetoresistance measurement system. (b) Schematic showing the setup for
measuring the GMR of individual nanowires inside a SEM.
III. Results And Discussion
3.1 Nanowire structure and resistance measurement
The structures of NiFe/Pt multilayer nanowires have been analysed at the nanoscale using SEM and
TEM [24]. Figure 2 shows a typical TEM image of the NiFe/Pt multilayer nanowires used in this work after
having been completely dissolved out of the AAO template. The NiFe/Pt nanowires have uniform diameters of
about 70 nm and an alternating NiFe and Pt layer structure. Group A nanowires were fabricated with layer
thicknesses of ~35 nm NiFe/~8 nm Pt while Group B were made with ~5 nm NiFe/~15 nm Pt. The NiFe and Pt
layers are polycrystalline with fcc lattice structure and the average grain size of both layers is 3–10 nm.
3. Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt ….
DOI: 10.9790/4861-07210915 www.iosrjournals.org 11 | Page
FIG. 2. Typical TEM image of an individual NiFe/Pt multilayer nanowire with alternating NiFe (grey) and Pt
(dark) layers.
The site-specific electrical resistance of individual NiFe/Pt nanowires was measured directly using two
manoeuvrable nichrome tip electrodes attached to in-situ SEM nanomanipulators [17,18]. The measured line
resistance (RL) of a typical circuit incorporating two nichrome electrodes connected directly to each other was
~133 Ω (Fig. 3(a)), which includes the resistances of the nichrome tips and wires. The probe electrodes attached
to the nanomanipulators can move freely inside the SEM with <10nm resolution to create conductive contacts at
chosen positions along an individual NiFe/Pt nanowire. Using this set up, the total electrical resistance (RT) of
measured circuits with no applied magnetic field could be determined. For example, a circuit incorporating a ~5
µm length of an individual NiFe(35 nm)/Pt(8 nm) multilayer nanowire was 2173 Ω (Fig. 3(b)). The current–
voltage (I–V) curves of RL and RT circuits were linear (Fig. 3(c)).
FIG. 3. Typical SEM images of the nanoscale electrical connection of (a) nichrome probe tips and (b) probe tips
to an individual NiFe/Pt nanowire. (c) I–V behaviour of a typical tip–tip circuit (solid black line) and tips–
NiFe/Pt nanowire circuit (dotted line).
4. Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt ….
DOI: 10.9790/4861-07210915 www.iosrjournals.org 12 | Page
1.2 Magnetoresistance effect of NiFe/Pt nanowires
The magnetoresistance of the nanowires, which is their change of electrical resistance when placed in
an external magnetic field, is affected by a number of factors including materials, microstructure and geometry
of the constituent layers, and strength and direction of applied magnetic field. Here the magnetoresistance effect
of individual NiFe/Pt multilayer nanowires has been measured in the CPP geometry by passing current along the
nanowire axes. The site-specific CPP-GMR measurements of individual NiFe(35 nm)/Pt(8 nm) and NiFe(5
nm)/Pt(15 nm) multilayered nanowires, and also single phase NiFe nanowires, were carried out with the
magnetic field applied both perpendicular and parallel to the wire axis.
The CPP-GMR effect of the individual NiFe/Pt nanowires was calculated as a ratio using GMR% =
[(RH − R0) / R0] × 100, where RH is the electrical resistance of the nanowire in the applied field H and R0 is the
resistance of the nanowire at zero field. Several measurements of GMR for different wires of the same structure
at room temperature and external magnetic fields H = 0–500 Oe have been made using the same technique. Fig.
4 shows GMR values for two similar wires at a given field H which were found to be consistent within < 0.3%
(Fig. 4), indicating that the wire microstructures are repeatable from a given electrodeposition process.
The observed CPP-GMR effect in the presence of a magnetic field depends on the scattering of
electrons within the layers and at interfaces between magnetic (NiFe) and nonmagnetic (Pt) layers [19,20,21].
There could also be boundary scattering of the electrons because the nanowire diameter used in this work is
small (~70 nm) [22]. As expected, for a given nanowire microstructure the GMR% for magnetic field applied
perpendicular to the wire axis is larger than the GMR% for the magnetic field applied parallel to the wire axis
due to the contribution from anisotropic magnetoresistance (AMR) (Fig. 4) [10,23]. To verify this the
magnetoresistance (MR%) of individual ~ 50 nm diameter, single phase NiFe nanowires were measured using
the same technique with external magnetic field (H) applied perpendicular and parallel to the wire axis. The
magnetoresistance was found to be ~ −0.19 % and ~ +0.05 % for H = 500 Oe applied perpendicular and parallel
to the wire axis respectively (Fig. 4(e)), which is consistent with the MR% of permalloy nanowires reported by
other research groups [24,25].
5. Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt ….
DOI: 10.9790/4861-07210915 www.iosrjournals.org 13 | Page
FIG. 4. Magnetoresistance effect of individual NiFe/Pt and single phase NiFe nanowires; resistance versus
applied external field H. Measurements from two different nanowires are given in each case. (a and c) H
perpendicular to the wire axis of individual NiFe(35 nm)/Pt(8 nm) and NiFe(5 nm)/Pt(15 nm) multilayer
nanowires respectively (black line), (b and d) H parallel to the wire axis of NiFe(35 nm)/Pt(8 nm) and NiFe(5
nm)/Pt(15 nm) multilayer nanowires respectively (dashed line) and (e) MR% of individual NiFe nanowires with
H perpendicular to the wire axis (black line) and H parallel to the wire axis (dashed line).
The optimal layer thickness of permalloy in NiFe/Cu multilayer nanowires was found by Dubois et al
to be 12 nm (with a thickness of 4nm for the Cu layers), which produced a GMR of >70% at low temperature
[23]. In the work presented here, the GMR value for a given H is strongly dependant on the layer thicknesses.
For external field up to H = 500 Oe, the GMR% measured in magnetic field applied perpendicular (θ = 90°) to
the wire axis was found to be 5.8 % for NiFe(35 nm)/Pt(8 nm) but reduced to 2.0 % for NiFe(5 nm)/Pt(15 nm)
(Fig. 4(a) and (c)). Similarly for the external magnetic field applied parallel (θ = 0°) to the wire axis the GMR
observed at 500 Oe was 5.3 % for NiFe(35 nm)/Pt(8 nm) but reduced to 1.6 % for the NiFe(5 nm)/Pt(15 nm)
(Fig. 4(b) and (d)).
The GMR of NiFe/Pt nanowires is affected by the thickness of the nonmagnetic layers, decreasing as
the non-magnetic layer thickness increases from 8nm to 15nm. This is because the dipole interaction field
between adjacent magnetic layers (which tends to align the magnetizations of the successive magnetic layers
antiparallel in the absence of an external magnetic field) reduces [9, 20,26], causing the magnetic layers to
orientate more randomly [9,27,28]. The GMR can also reduce rapidly as the thickness of the non-magnetic layer
exceeds the non-magnetic material’s spin flip diffusion length since the electrons, due to the increasing number
of spin flip events, no longer retain their polarization from the previous magnetic layer as they reach the next
magnetic layer [22,29]. For the NiFe/Pt system measured here, the GMR% may also decrease with increasing Pt
layer thickness due to the increasing resistance contribution of Pt (which has a higher resistivity than NiFe) to
the overall wire resistance [18,27].
The applied maximum external magnetic field H for GMR measurements in this work was smaller than
that required to achieve GMR saturation and there is limited detailed data in the literature on GMR in the low
field 0–500 Oe regime. For multilayer nanowires with nonmagnetic layer thickness (< 10 nm), the averaged
GMR% at 500 Oe, determined using GMR% = [(RH − R0) / R0] × 100, is ~1.8% for FeNiCo/Cu [19], 12% for
Co/Cu [30] and 2.2% for CoNiCu/Cu [31]. The GMR values measured here for the individual NiFe/Pt
nanowires are of similar magnitude, but lower than the Co/Cu nanowires.
Previous works have concentrated on nanowires embedded in templates, reporting average GMR
values calculated from estimated values of contact resistance of the wires [9,10,25,27]. The measurements
performed with the new site-specific in-situ technique presented here, though, are directly made on individual
nanowires and not based on an average, so the calculated GMR values are an accurate result for future
applications. Furthermore, the measurements are performed in-situ in the SEM so the nanowires can be
observed in real-time during testing. For these NiFe/Pt nanowires, under the chosen current and magnetic field
conditions, no microstructural changes during the GMR measurements were seen but failure of similar NiFe/Pt
multilayer nanowires at higher current densities has been observed in previous work [18].
IV. Conclusion
The magnetoresistance effect of ~70 nm diameter individual NiFe/Pt multilayered nanowires has been
investigated using a new site-specific technique for in-situ GMR measurement. An accurate measurement of the
GMR effect of the magnetic NiFe/Pt multilayer nanowires was carried out in the current perpendicular to plane
(CPP) geometry. The CPP-GMR effect of the individual NiFe/Pt nanowires with two different layer thickness
6. Site-specific measurement of the giant magnetoresistance (GMR) of individual NiFe/Pt ….
DOI: 10.9790/4861-07210915 www.iosrjournals.org 14 | Page
geometries was measured at variable magnetic field H up to 500 Oe and with different directions of applied
magnetic field with respect to the nanowire axis. The CPP-GMR was dependent on both magnetic field
orientation and layer thicknesses, being maximum for NiFe(35 nm)/Pt(8 nm) and H perpendicular to the wire
axis. The GMR % of individual NiFe(35 nm)/Pt(8 nm) and NiFe(5 nm)/Pt(15 nm) nanowires measured with H
= 500 Oe applied perpendicular to the wire axis was 5.8% and 2.0%; and for H = 500 Oe parallel to the wire
axis was 5.3% and 1.6% respectively. For individual single phase NiFe nanowires, anisotropic
magnetoresistance was measured as −0.19% for H = 500 Oe applied perpendicular to the wire axis and +0.05%
for H = 500 Oe applied parallel to the wire axis. The ability to measure magnetic properties of individual
multilayer nanowires and other nanocomponents at specific locations will be of significant benefit as nanowire
systems become more diverse and inhomogeneous, and essential for industrial applications in nanodevices and
GMR sensors..
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