scholarly journals Effect of Cu Substitution on Magnetic and DC Electrical Resistivity Properties of Ni-Zn Nano Ferrites

2021 ◽  
Author(s):  
K. Chandramouli ◽  
P. Anantha Rao ◽  
B. Suryanarayana ◽  
Vemuri Raghavendra ◽  
D. Parajuli ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Negative Temperature Coefficient ◽  
Sol Gel ◽  
Combustion Process ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Content ◽  
Auto Combustion ◽  
Resultant Material

Abstract Cu substituted Ni0.5Zn0.5-xCuxFe2O4 (x = 0, 0.1, 0.2, 0.3 and 0.4) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Cu content increases. The sizes of the crystallites are also decreasing in the range of 42.68 nm to 21.75 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FTIR spectra are similar to that of the precursor. The increment in the copper content increases the DC conductivity. The electrical resistivity decrease with increase in the temperature, i.e. it has a negative temperature coefficient with resistance similar to semiconductors. The remnant ratios R obtained from VSM show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

scholarly journals Effect of Al3+ Substitution On Magnetic and DC Electrical Resistivity Properties of NiZnCu Nanoferrites

2021 ◽  
Author(s):  
N MURALI
Keyword(s):  
Electrical Resistivity ◽  
Negative Temperature Coefficient ◽  
Sol Gel ◽  
Combustion Process ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion ◽  
Ft Ir ◽  
Resultant Material

Abstract Al substituted Ni0.4Zn0.35Cu0.25Fe2-xAlxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Al3+ content increases. The sizes of the crystallites are also decreasing in the range of 32.15 nm to 22.89 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FT-IR spectra are similar to that of the precursor. The increment in the Al3+ content increases the DC conductivity. The electrical resistivity decrease with an increase in the temperature, i.e., it has a negative temperature coefficient with resistance similar to semiconductors. VSM results show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

scholarly journals DC Electrical Resistivity and Magnetic Properties of Co Substituted NiCuZn Nano Ferrite

2021 ◽  
Author(s):  
Kanta Jayadev ◽  
M. K. Raju ◽  
N MURALI ◽  
Parajuli D ◽  
K. Samatha
Keyword(s):  
Electrical Resistivity ◽  
Negative Temperature Coefficient ◽  
Sol Gel ◽  
Combustion Process ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Octahedral Sites ◽  
Auto Combustion ◽  
Resultant Material

Abstract Co substituted Ni0.3-xCoxCu25Zn0.45Fe2O4 (x = 0, 0.05, 0.1, 0.15 and 0.2) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Co content increases. The sizes of the crystallites are in the range of 20.18–26.24 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FTIR spectra are similar to that of the precursor. The increment on the Co content increases the DC conductivity. The electrical resistivity decrease with increase in the temperature, i.e. it has a negative temperature coefficient with resistance similar to semiconductors. The remnant ratios R obtained from VSM show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

IMPROVED MAGNETIC PROPERTIES OF Sm COMBINING Co OR/AND Zn SUBSTITUTED BARIUM M-TYPE HEXAFERRITES

2012 ◽  
Vol 26 (26) ◽  
pp. 1250141 ◽  
Author(s):  
Y. B. HAN ◽  
J. SHA ◽  
L. N. SUN ◽  
Q. TANG ◽  
Q. LU ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Phase Composition ◽  
Magnetocrystalline Anisotropy ◽  
Sol Gel ◽  
Combustion Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Hexaferrites ◽  
Auto Combustion ◽  
Magnetic Dilution

Sm (Co or/and Zn) substituted nanocrystalline barium hexaferrites were synthesized by the sol–gel auto-combustion process, then X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to characterize and discuss the phase composition and the magnetic properties of the as-prepared barium hexaferrites. All results showed that the phase composition and magnetic properties were closely related to the doping elements and x. Owing to hyperfine field, canting spin, magnetic dilution and impurity phases, the saturation magnetization (Ms) of all samples increased firstly, and then decreased. Considering the crystallization, the magnetocrystalline anisotropy and the ions occupancy, the doping elements and x critically affected the coercivity (Hc). Compared the magnetic properties of all the samples, it is concluded that Zn 2+ and Co 2+ influenced each other and Zn 2+ occupied 4f2 sites prior to Co 2+, which led to the increase of Ms and the decrease of Hc.

scholarly journals Y3+ substituted Sr-hexaferrites: sol-gel synthesis, structural, magnetic and electrical characterization

Cerâmica ◽  
2019 ◽  
Vol 65 (374) ◽  
pp. 274-281 ◽  
Author(s):  
S. S. Satpute ◽  
S. R. Wadgane ◽  
S. R. Kadam ◽  
D. R. Mane ◽  
R. H. Kadam
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Combustion Method ◽  
Hexagonal Structure ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Morphological Studies ◽  
Auto Combustion

Abstract Y3+ substituted strontium hexaferrites having chemical composition SrYxFe12-xO19 (x= 0.0, 0.5, 1.0, 1.5) were successfully synthesized by sol-gel auto-combustion method. The structural and morphological studies of prepared samples were investigated by using X-ray diffraction technique, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy. The X-ray diffraction pattern confirmed the single-phase hexagonal structure of yttrium substituted strontium ferrite and the lattice parameters a and c increased with the substitution of Y3+ ions. The crystallite size also varied with x content from 60 to 80 nm. The morphology was studied by FE-SEM, and the grain size of nanoparticles ranged from 44 to 130 nm. The magnetic properties were investigated by using vibrating sample magnetometer. The value of saturation magnetization decreased from 49.60 to 35.40 emu/g. The dielectric constant decreased non-linearly whereas the electrical dc resistivity increased with the yttrium concentration in strontium hexaferrite.

scholarly journals Green synthesis and characterization of hexaferrite strontium-perovskite strontium photocatalyst nanocomposites

2020 ◽  
Vol 43 (1) ◽  
pp. 26-42 ◽  
Author(s):  
Zahra Hajian Karahroudi ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi
Keyword(s):  
Magnetic Properties ◽  
Green Synthesis ◽  
Sol Gel ◽  
Synthesis Method ◽  
Combustion Method ◽  
Lemon Juice ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.

Aging of iron manganite negative temperature coefficient thermistors

1998 ◽  
Vol 13 (5) ◽  
pp. 1238-1242 ◽  
Author(s):  
T. Battault ◽  
R. Legros ◽  
A. Rousset
Keyword(s):  
Temperature Coefficient ◽  
Spinel Structure ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Octahedral Sites ◽  
Before And After ◽  
Structural Equilibrium ◽  
Electrical Data

“Aging,” defined as the drift of resistance with temperature after 1000 h, was investigated for iron manganite temperature coefficient thermistors. For these devices, aging is relatively large, about 10%. The cationic distributions before and after aging were determined by Mössbauer spectroscopy. These distributions explain all the x-ray diffraction and correlated electrical data. The origin of the aging observed on iron manganites thermistors has been identified. It is due to the migration of Fe3+ ions from tetrahedral to octahedral sites of the spinel structure in order to reach a structural equilibrium.

scholarly journals Effect of Re and Tm-site on morphology structure and optical band gap of ReTmO3 (Re: La, Ce, Nd, Gd, Dy, Y and Tm: Fe, Cr) prepared by sol-gel method

2018 ◽  
Vol 64 (4) ◽  
pp. 381
Author(s):  
Muhammad Tufiq Jamil ◽  
Javed Ahmad ◽  
Syed Hamad Bukhari ◽  
Murtaza Saleem
Keyword(s):  
Band Gap ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Average Grain Size ◽  
Auto Combustion ◽  
Uv Visible

Rare earth nano sized pollycrystalline orthoferrites and orthocromites ReT mO3 (Re = La, Nd, Gd, Dy, Y and T m = Fe, Cr) have been synthesized by sol-gel auto combustion citrate method. The samples have been characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and UV-visible spectroscopy. The samples are single phase as confirmed by XRD analysis and correspond to the orthorhombic crystal symmetry with space group pbnm. Debye Scherer formula and Williamson Hall analysis have been used to calculate the average grain size which is consistent with that of determined from SEM analysis and varied between 25-75 nm. The elemental compositions of all samples have been checked by EDX analysis. Different crystallographic parameters are calculated with strong structural correlation among Re and Tm sites. The optical energy band gap has been calculated by using Tauc relation estimated to be in the range of 1.77 - 1.87 eV and 2.77 - 3.14 eV, for ReFeO3 and ReCrO3, respectively.

scholarly journals Frequency and Temperature Dependent Dielectric Response of Fe3O4 Nano-crytallites

2014 ◽  
Vol 6 (3) ◽  
pp. 399-406 ◽  
Author(s):  
M. Z. Ansar ◽  
S. Atiq ◽  
K. Alamgir ◽  
S. Nadeem
Keyword(s):  
Magnetite Nanoparticles ◽  
Sol Gel ◽  
Dielectric Behavior ◽  
Tangent Loss ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Dielectric Tangent Loss ◽  
Auto Combustion ◽  
Combustion Technique

Magnetite nanoparticles have been prepared by using sol-gel auto combustion technique. The samples are prepared by using different concentrations of fuel. Structural characterization has been done using X-Ray diffraction technique and it was observed that fuel concentration can affect the structural properties of Magnetite nanoparticles. The dielectric properties for all the samples such as dielectric constant (??), dielectric tangent loss (tan ?) and dielectric loss factor (??) have been studied as a function of frequency and temperature in the range 10 Hz–20 MHz  and it was found that these nanoparticles can be used in microwave devices because of their good dielectric behavior. © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v6i3.17938 J. Sci. Res. 6 (3), 399-406 (2014)

scholarly journals Structural, Optical, and Catalytic Properties of MgCr2O4 Spinel-Type Nanostructures Synthesized by Sol–Gel Auto-Combustion Method

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1476
Author(s):  
Vasyl Mykhailovych ◽  
Andrii Kanak ◽  
Ştefana Cojocaru ◽  
Elena-Daniela Chitoiu-Arsene ◽  
Mircea Nicolae Palamaru ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Catalytic Properties ◽  
Spinel Phase ◽  
Sol Gel ◽  
Combustion Method ◽  
Temperature Treatment ◽  
X Ray Diffraction ◽  
Spinel Type ◽  
X Ray ◽  
Auto Combustion

Spinel chromite nanoparticles are prospective candidates for a variety of applications from catalysis to depollution. In this work, we used a sol–gel auto-combustion method to synthesize spinel-type MgCr2O4 nanoparticles by using fructose (FS), tartaric acid (TA), and hexamethylenetetramine (HMTA) as chelating/fuel agents. The optimal temperature treatment for the formation of impurity-free MgCr2O4 nanostructures was found to range from 500 to 750 °C. Fourier transform infrared (FTIR) spectroscopy was used to determine the lattice vibrations of the corresponding chemical bonds from octahedral and tetrahedral positions, and the optical band gap was calculated from UV–VIS spectrophotometry. The stabilization of the spinel phase was proved by X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis. From field-emission scanning electron microscopy (FE-SEM), we found that the size of the constituent particles ranged from 10 to 40 nm. The catalytic activity of the as-prepared MgCr2O4 nanocrystals synthesized by using tartaric acid as a chelating/fuel agent was tested on the decomposition of hydrogen peroxide. In particular, we found that the nature of the chelating/fuel agent as well as the energy released during the auto-combustion played an important role on the structural, optical, and catalytic properties of MgCr2O4 nanoparticles obtained by this synthetic route.

Sign in / Sign up

Export Citation Format

Share Document