Structural and electrical properties of Cu-doped Ni–Zn nanocrystalline ferrites for MLCI applications

Abstract

Polycrystalline Cu substituted Ni–Zn ferrites with chemical composition Ni[Formula: see text]Zn[Formula: see text]-Cu[Formula: see text]Fe2O4 (x = 0.00 to 0.25 in steps of 0.05) have been prepared by citrate gel autocombustion method. The samples for electrical properties have been sintered at 900[Formula: see text]C for 4 h. The X-ray diffraction patterns of all samples indicate the formation of single phase spinel cubic structure. The value of lattice parameter is decreases with increasing Cu concentration. The estimated cation distribution can be derived from X-ray diffraction intensity calculations and IR spectra. The tetrahedral and octahedral bond lengths, bond angles, cation–cation and cation–anion distances were calculated by using experimental lattice parameter and oxygen positional parameters. It is observed that Cu ions are distributed in octahedral site and subsequently Ni and Fe ions in tetrahedral site. The grain size of all samples has been calculated by Scanning Electron Microscopy (SEM) images. The variations in DC electrical resistivity and dielectric constant have been explained on the basis of proposed cation distribution.

Morphological analysis of Cu substituted Ni\Zn in Ni-Zn ferrites

“…From the micrographs, the cupper content has improved the homogeneous spherical grain and low agglomeration similar to the result of Sundararajan et al [15]. The grain size was found to be in the ranges from 130 to 246 nm with 130 nm for base composition, 183 nm for x=0.20, and the highest average grain size is 246 nm for x=0.15 similar to the previous results [18].…”

Correlation between the Magnetic and DC resistivity studies of Cu substituted Ni and Zn in Ni-Zn ferrites

“…Ferrites have higher resistivity due to unequal antimagnetic moments giving rise to higher spontaneous magnetization. Moreover, they have a negative exchange integral affected by an interatomic distance which obstructs the flow of electrons [14]. However, their saturation permeability, coercivity, susceptibility, Curie temperature, etc.…”