scholarly journals Structural, Electrical, Dielectric, and Magnetic Properties of Cd2+ Substituted Nickel Ferrite Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
B. H. Devmunde ◽  
A. V. Raut ◽  
S. D. Birajdar ◽  
S. J. Shukla ◽  
D. R. Shengule ◽  
...  
Keyword(s):  
Ac Susceptibility ◽  
Sol Gel ◽  
Interfacial Polarization ◽  
Ferrite Nanoparticles ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Nickel Ferrite Nanoparticles ◽  
Phase Spinel ◽  
Intergranular Diffusion ◽  
Fe Ions

In the present investigation structural, electric, magnetic, and frequency dependent dielectric properties of Ni1-xCdxFe2O4 ferrite nanoparticles (NPs) (where x=0.2, 0.4, 0.6, and 0.8) prepared by sol-gel autocombustion method were studied. The crystallite size (t) (46.89~58.40 nm) was estimated from X-ray diffraction data with the postconfirmation of single phase spinel structure. Spherical shaped, fused grain nature with intergranular diffusion in Ni1-xCdxFe2O4 NPs was observed in scanning electron micrographs. The value of loss tangent (tan⁡δ) decreases exponentially with an increasing frequency indicating normal Maxwell-Wagner type dielectric dispersion due to interfacial polarization. Decreasing values of Curie temperature (TC) from 860°C to 566°C with increasing Cd2+ content x in Ni1-xCdxFe2O4 NPs were determined from AC-Susceptibility. Activation energy ΔE ranges within 0.03~0.15 eV. Decreasing magnetic saturation Ms, coercivity Hc, and magneton number nB values show the effect on nonmagnetic Cd2+ ions over magnetic Ni2+ and Fe ions.

scholarly journals Preparation and Characterization of Nickel Ferrite-SiO2/Ag Core/Shell Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
I. G. Blanco-Esqueda ◽  
G. Ortega-Zarzosa ◽  
J. R. Martínez ◽  
A. L. Guerrero
Keyword(s):  
Silver Nanoparticles ◽  
Nickel Ferrite ◽  
Sol Gel ◽  
Ferrite Nanoparticles ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Magnetic Composites ◽  
Nickel Ferrite Nanoparticles ◽  
Gel Technique

Magnetic composites with silver nanoparticles bonded to their surface were successfully prepared using a simple chemical method. By means of a sol-gel technique, nickel ferrite nanoparticles have been prepared and coated with silica to control and avoid their magnetic agglomeration. The structural and magnetic properties of the nanoparticles were studied in function of the annealing temperature. Then, silver nanoparticles were incorporated by hydrolysis-condensation of tetraethyl orthosilicate, which contains silver nitrate on the surface of the nickel ferrite-SiO2core/shell. Samples were characterized using X-ray diffraction, IR spectroscopy, SEM, and magnetometry. Results show that the silica covered the nickel ferrite nanoparticles and the silver nanoparticles remain stable in the surface of the composite.

The Structure and Ferromagnetic Properties of the Single Phase Bi0.95Eu0.05Fe0.95Co0.05O3 Nanoparticles Prepared by Sol-Gel

2012 ◽  
Vol 512-515 ◽  
pp. 1434-1437
Author(s):  
Xing Ao Li ◽  
Peng Li ◽  
Yong Tao Li ◽  
Jian Ping Yang ◽  
Qiu Fei Bai ◽  
...  
Keyword(s):  
Single Phase ◽  
Sol Gel ◽  
Mixed Valence ◽  
Magnetic Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Valence States ◽  
Sol Gel Process ◽  
X Ray Absorption ◽  
Fe Ions

Bi0.95Eu0.05Fe0.95Co0.05O3 Nanoparticles sample was prepared by sol-gel process. The microstructure of samples was analysised by X-ray diffraction(XRD), the result indicated that it was the single phase rhombohedral perovskite structure. The morphology of samples was measured by scanning electron microsopy(SEM), the SEM photograph of samples indicated that the nanoparticles of Bi0.95Eu0.05Fe0.95Co0.05O3 sample were small than that of BiFeO3. The valence states of Fe ions in the samples was analysised by the X-ray absorption spectroscopy（XAS）. The XAS of Fe2p showed that it was the mixed valence states (Fe2+ and Fe3+) of Fe ions in samples, and the binding energy of Bi0.95Eu0.05Fe0.95Co0.05O3 was bigger than that of BiFeO3.The magnetic characteristics of the samples were measured by vibrating sample magnetometer (VSM)，the results showed that the weak metamagnetism were obtained from clear hysteresis loop and the magnetic saturation reached 0.408emu/g，compared with BiFeO3 sample, the magnetic properties were significantly enhanced.

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.

Surface Spin-glass Freezing and Blocking in NiFe2O4 Nanoparticles

2010 ◽  
Vol 1256 ◽  
Author(s):  
Kashif Nadeem ◽  
Heinz Krenn
Keyword(s):  
Low Temperature ◽  
Spin Glass ◽  
Ac Susceptibility ◽  
Sol Gel ◽  
Ferrite Nanoparticles ◽  
Core Shell ◽  
Temperature Hysteresis ◽  
Zero Field ◽  
Temperature Peak ◽  
Surface Spin

AbstractWe prepared single-phase nickel ferrite nanoparticles separated by silicon dioxide using sol-gel method with tetraethyl orthosilicate (TEOS) as a precursor for SiO2. The magnetic properties are investigated by using SQUID-magnetometry over a broad temperature range (4.2 – 350 K), magnetic field (2–70,000 Oe) and frequency (0.1 – 1000 Hz) range. The particle size is in the range 8 – 12 nm. Exchange bias and spin disorder appear at the core-shell interface due to broken bonds on the surface. Disorder and core-shell interaction induces spin-glass freezing which is manifested by a low temperature peak in the AC susceptibility well separated from magnetic blocking peak. This low temperature peak is assigned to spin-glass freezing. The proof of spin-glass freezing is managed by zero field cooled/field cooled (ZFC/FC), frequency and DC field dependence of AC susceptibility, low temperature hysteresis loop and time dependent thermoremanent magnetization at different temperatures. All the measurements stated above signify blocking/unblocking at higher temperatures and surface spin-glass freezing at low temperatures. The aim of our work is to contribute to a better understanding of “spin-frozen” magnetic ferrite nanoparticles at diameters 8 – 12 nm which could be important in future for stabilizing the magnetic state of “core-shell”-structured nanomagnets.

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