Effect of Cr Substitution on Magnetic Properties of Mg Nanoferrites Synthesized by Citrate-Gel Auto Combustion Method

A series of Mg-Cr nanoferrites with the chemical formula MgCrxFe2−xO4 () were synthesized by Citrate-Gel auto combustion method. The formation of single phase cubic spinel structure of the samples was confirmed by X-ray diffraction (XRD) analysis. It is observed that with the increase in the paramagnetic Cr content, the particle size of the ferrite compositions has decreased from 23 nm to 7 nm. Faraday magnetic Susceptibility Balance was used to measure the Magnetic susceptibility of synthesized samples that confirmed the paramagnetic nature of the ferrites. Vibrating Sample Magnetometer (VSM) was used to measure the Magnetic properties of nanoferrites under investigation at room temperature under the applied magnetic field of 15 kOe. With the increase in Cr3+ concentration, the saturation magnetization has decreased from 11 emu/g to 1.5 emu/g

Influence of rare earth ion doping (Ce and Dy) on electrical and magnetic properties of cobalt ferrites

Ce and Dy substituted Cobalt ferrites with the chemical composition CoCexDyxFe2-2xO4 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) were synthesized through the chemical route, citrate-gel auto-combustion method. The structural characterization was carried out with the help of XRD Rieveld analysis, SEM and EDAX analysis. Formation of spinel cubic structure of the ferrites was confirmed by XRD analysis. SEM and EDAX results show that the particles are homogeneous with slight agglomeration without any impurity pickup. The effect of RE ion doping (Ce and Dy) on the dielectric, magnetic and impedance studies was systematically investigated by LCR meter, Vibrating Sample Magnetometer and Impedance analyzer respectively at room temperature in the frequency range of 10 Hz-10 MHz. Various dielectric parameters viz., dielectric constant, dielectric loss and ac conductivity were measured. The dielectric constant of all the ferrite compositions shows normal dielectric dispersion of ferrites with frequency. Impedance analysis confirms that the conduction in present ferrites is majorly due to the grain boundary mechanism. Ferrite sample with x = 0.03 show high dielectric constant, low dielectric loss and hence can be utilized in high frequency electromagnetic devices. Magnetization measurements indicate that with increase in Ce and Dy content in cobalt ferrites, the magnetization values decreased and coercivity has increased

Superparamagnetic behavior of indium substituted NiCuZn nano ferrites

Nano structured indium substituted NiCuZu ferrites with chemical composition Ni05Cu0.25Zn0.25 Fe2-xInxO4 (0.0 <= x <= 0.4) were prepared using citrate gel method. The XRD analysis confirmed the formation of single phased cubic spinet structure with a crystallite size ranging from 25 to 34 nm. The morphology of the prepared samples was studied using transmission electron microscopy and the thermal growth of the samples was analyzed by thermo gravimetric analysis and differential thermal analysis. Magnetic properties such as the Curie temperature and the temperature dependence magnetization studies of the samples were carried out using vibrating sample magnetometer. From the temperature dependence of both the field cooled and Zero field cooled magnetization measurements in the temperature range 50-350 K under an applied field of 500 Oe, the blocking temperature (TO was estimated to be 325 K. Above T-b the material shows superparamagnetic behavior which makes the material desirable for biomedical applications. Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserve

High temperature dielectric studies of indium-substituted NiCuZn nanoferrites

In this study, indium (In3+)-substituted NiCuZn nanostructured ceramic ferrites with a chemical composition of Ni0.5Cu0.25Zn0.25Fe2-xInxO4 (0.0 <= x <= 0.5) were prepared by chemical synthesis involving sol-gel chemistry. Single phased cubic spinel structure materials were prepared successfully according to X-ray diffraction and transmission electron microscopy analyses. The dielectric properties of the prepared ferrites were measured using an LCR HiTester at temperatures ranging from room temperature to 300 degrees C at different frequencies from 10(2) Hz to 5 x 10(6) Hz. The variations in the dielectric parameters epsilon' and (tan delta) with temperature demonstrated the frequency- and temperature-dependent characteristics due to electron hopping between the ions. The materials had low dielectric loss values in the high frequency range at all temperatures, which makes them suitable for high frequency microwave applications. A qualitative explanation is provided for the dependences of the dielectric constant and dielectric loss tangent on the frequency, temperature, and composition. Mossbauer spectroscopy was employed at room temperature to characterize the magnetic behavior