B. G. Toksha

Electrical and magnetic properties of Cr3+ substituted nanocrystalline nickel ferrite

The magnetic and electrical properties of Cr3+ substituted nickel ferrite synthesized by wet chemical route have been studied. Particle size measured from x-ray diffraction and from transmission electron microscopy images confirms the nanosize dimension of prepared particles. Magnetic parameters such as coercivity and saturation magnetization are measured from vibrating sample magnetometer. Magnetization, ac susceptibility, electrical resistivity, and Mossbauer measurements were carried out. Electrical properties such as ac resistivity as a function of frequency and dc resistivity as a function of temperature were studied for various Cr3+ substitutions in nickel ferrite. The dielectric properties such as dielectric constant (e′) and dielectric loss (e″) were also studied. The dielectric constant and dielectric loss obtained for the ferrites prepared through wet chemical route posses a value lower than that of the ceramically prepared samples of the same composition. The resistivity obtained is higher than...

Influence of Ce4+ ions on the structural and magnetic properties of NiFe2O4

The effect of Ce4+ substitution in NiFe2O4, with a chemical formula Ni1-2xCexFe2O4 (0 ≤ x ≤ 0.25), ferrite prepared by a solid-state reaction is presented in this paper. Ce4+ ions enter the NiFe2O4 lattice by replacing Ni2+ and swell the lattice. This enlarges the lattice constant, which results in a moderate distortion of the lattice. The r.m.s. strain increases from 0.411 × 10−3 to 0.471 × 10−3 with increasing Ce4+ content. SEM images revealed that Ce4+ promotes grain growth in NiFe2O4. It was also revealed that x-ray density and porosity decreases, whereas a significant increase in the bulk density is observed with the Ce4+ content. Substitution of Ce4+ for Ni2+ caused a decrease in the saturation magnetization from 41.3 to 25.12 emu/g and a decrease in the Curie temperature of the nickel ferrite from 830 to 594 K, whereas the coercivity increased from 59.48 to 458.25 Oe.

STRUCTURAL PROPERTIES AND CATION DISTRIBUTION OF Co{Zn NANOFERRITES

The soft spinel ferrite system having the general formula Co1-xZnxFe2O4 with x varying from 0.0 to 0.7 has been prepared by wet-chemical co-precipitation technique. The prepared samples were characterized by XRD technique. The analysis of XRD pattern revealed the formation of single-phase cubic spinel structure. The Bragg peaks in XRD pattern are broader indicating fine particle nature of the sample. XRD data have been used to study structural parameter and cationic distribution in Co–Zn ferrite. The particle size is of nanometer dimension. Cation distribution results suggest that Co2+ occupy B-site, Zn2+ occupy A-site, and Fe3+ occupy both the A- and B-site.