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)

Ruderman-Kittel-Kasuya-Yosida Magnetic Interactions in Chemically Synthesized Zn-Fe-AlO Nanocrystallites

2013 ◽  
Vol 748 ◽  
pp. 65-69
Author(s):  
Asif Mahmood ◽  
Yousef Al-Zeghayer
Keyword(s):  
Magnetic Interactions ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Ionic Radii ◽  
X Ray ◽  
Wurtzite Crystal Structure ◽  
Auto Combustion ◽  
Phase Pure ◽  
Combustion Technique ◽  
Lower Resistivity

Chemically derived auto-combustion technique is employed to synthesize the Zn0.95-xFe0.05AlxO (x=00.07 in 0.02 increment) nanocrystallites. X-ray diffraction studies of all compositions revealed the phase pure wurtzite crystal structure with space group P63mc. The lattice parameters and crystallite size is changed with doping of Al attributed to the diversity in size of ionic radii. Temperature dependent electrical resistivity shows a decreased trend with the rise of temperature, confirming the semiconductor nature of compositions. The lower resistivity and enhanced saturation magnetization values in Al doped compositions correspond to the increase in density of carriers. Carriers mediated RKKY interactions are found to observe for enhancement of magnetization.

scholarly journals Fabrication of H2S gas sensors using ZnxCu1-xFe2O4 nanoparticles

2020 ◽  
Vol 126 (7) ◽  
Author(s):  
Mohammad Abu Haija ◽  
Mariem Chamakh ◽  
Israa Othman ◽  
Fawzi Banat ◽  
Ahmad I. Ayesh
Keyword(s):  
Gas Sensors ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Ferrite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion ◽  
Multiple Cycles ◽  
Cubic Structure ◽  
Combustion Technique

Abstract Spinel ferrite nanoparticles can be easily retrieved and utilized for multiple cycles due to their magnetic properties. In this work, nanoparticles of a ZnxCu1-xFe2O4 composition were synthesized by employing a sol–gel auto-combustion technique. The morphology, composition, and crystal structure were examined using scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The produced nanoparticles are in the range of 30–70 nm and manifest spinel cubic structure. The nanoparticles were tested for their sensitivity to H2 and H2S gases, and the Cu-based spinel ferrite nanoparticles were found the most sensitive and selective to H2S gas. Their enhanced response to H2S gas was attributed to the production of metallic CuFeS2 that manifest higher electrical conductivity as compared with CuFe2O4. The fabricated sensors are functional at low temperatures, and consequently, they need low operational power. They are also simple to fabricate with appropriate cost.

Synthesis, Characterization and Magnetic Properties of Cobalt Ferrite Nanoparticles Prepared by Glycine Assisted Sol-Gel Auto-Combustion Technique

2013 ◽  
Vol 209 ◽  
pp. 31-34 ◽  
Author(s):  
A.B. Shinde ◽  
G.H. Kale ◽  
V.N. Dhage ◽  
P.K. Gaikwad ◽  
K.M. Jadhav
Keyword(s):  
Electron Microscopy ◽  
Cobalt Ferrite ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Auto Combustion ◽  
Ray Density ◽  
Combustion Technique ◽  
Scanning Electron

Nano-particles of (38 nm size) cobalt ferrite (CoFe2O4) were synthesized by sol-gel auto-combustion technique using high purity metal nitrates and glycine as a fuel. The characterization studies were conducted by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The analysis of X-ray diffraction pattern suggests that, the prepared CoFe2O4 spinel ferrite possess single phase cubic spinel structure. The most intense peak (311) of the XRD pattern was used to determine the crystallite size. lattice constant and X-ray density were calculated by using XRD data. The values of lattice constant and X-ray density are found to in the reported range but slightly higher as compared to bulk CoFe2O4 sample. The surface morphology of the CoFe2O4samples was examined through scanning electron microscopy (SEM) technique. The result of SEM analysis shows that grain size is of the order of 62 nm. The CoFe2O4 nano-particle exhibit ferromagnetic behavior having saturation magnetization (Ms) and coercivity (Hc) values in the range of 83 emu/gm and 1381 Oe respectively. The high values of saturation magnetization and coercivity gives the evidence of nanocrystalline nature of the prepared CoFe2O4 spinel ferrite.

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.

Structural, Magnetic and Dielectric Analysis of Higher Magnetic Mn Doped Zn-Cr Oxide Nanoparticles

2021 ◽  
Vol 9 (VI) ◽  
pp. 95-102
Author(s):  
S. D. Balsure
Keyword(s):  
Type Strain ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Xrd Analysis ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Microstructural Parameters ◽  
Auto Combustion ◽  
Mn Doped ◽  
Combustion Technique

Higher magnetic Mn doped Zn-Cr oxide nanoparticles with general compositional formula MxZn0.95-xCr0.05O have been synthesized by using sol-gel auto combustion technique. Room temperature X-ray diffraction (XRD) technique has been employed to study the structural and microstructural parameters of the as-prepared samples. XRD analysis confirms the phase purity and hexagonal wurtzite structure of all the samples. Replacement of Zn2+ ions by Mn2+ ions shifts peak positions slightly towards the lower angles which in turn expands the lattice lengths ‘a’ from 3.2487 to 3.2528 Å and ‘c’ from 5.2043 to 5.2118 Å. Crystallite size obtained from Scherrer equation was confirmed by Williamson – Hall (W-H) and size – strain plot methods (SSP). Both W-H and SSP methods reveals the tensile type strain for undoped sample and comprehensive type strain for Mn2+ doped samples. Magnetic properties were investigated by using vibrating sample magnetometer. Diluted ferromagnetic behaviour is observed for all the samples and saturation magnetization (MS) increases from 0.0514 to 0.1163 emu/gm. Two-probe technique was employed to understand the dielectric behaviour of the samples as a function of frequency. At lower frequency region, both dielectric constant () and dielectric loss tangent (tan ) shows higher values and decreases with the increasing applied frequency.

scholarly journals Synthesis, Characterization, and NH3 Sensing Properties of (Zn0.7 Mn0.3-x Cex Fe2O4) Nano-Ferrite

2021 ◽  
Vol 2114 (1) ◽  
pp. 012040
Author(s):  
Laith Saheb ◽  
Tagreed M. Al-Saadi
Keyword(s):  
Recovery Time ◽  
Particle Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Properties ◽  
Auto Combustion ◽  
Cubic Structure ◽  
Sensing Characteristics ◽  
Combustion Technique ◽  
Higher Sensitivity

Abstract This study includes the preparation of novel nano ferrite (Zn0.7 Mn0.3-x Cex Fe2O4) by using the auto combustion technique. For the following molar values, the percentage x was calculated: 0.0, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3. The nano-ferrite was calcined for 2 hours at 500°C. The energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD) and field emission scanning electron microscopy FE-SEM was used to examine structural, morphological, and sensing properties. The spinel cubic structure was revealed by XRD findings. The particle distribution was shown to contain voids by FE-SEM. The testing of sensing characteristics to NH3 gas indicated that the synthesized nano-ferrite has a small response time ranging from (15.3-25.2) s as well as a small recovery time between (36-58.5) s, also has a higher sensitivity of about 72.23%.

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.

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