Impact of Cr Substitution on Structural, Magnetic, Electric and Impedance Study of Mn-Ni-Zn Ferrites

Abstract

A series of Cr 3+ -substituted Mn-Ni–Zn ferrites; Mn 0.5 Ni 0.1 Zn 0.4 Fe 2-x Cr x O 4 ( x = 0.0 - 0.4 in a step of 0.1) were prepared by traditional solid-state reaction route. The structural, magnetic, dielectric properties and impedance spectroscopy of these compositions were studied. Phase identification and lattice constant (a 0 ) determination were carried out by X-ray diffraction (XRD). The XRD patterns established the fabrication of a single-phase spinel structure. The FESEM micrographs exposed that the average grain size ( ) increased slightly with chromium (Cr) substitution and then decreased for a higher concentration of chromium in the composition. The real part of initial permeability ( ) diminished owing to the enhanced porosity of the compositions with the increase of Cr 3+ content in the composition. The highest relative quality factor (RQF) was attained for the samples with x = 0.1. The magnetic hysteresis was investigated to know the effect of Cr 3+ substitution in the composition of the magnetic properties. The decrease of saturation magnetization ( M s ) with an enhancement in Cr 3+ might be triggered by switching of Fe 3+ ions from octahedral to tetrahedral site. The samples with x = 0.1 exhibited the highest anisotropy constant ( K ). Curie temperatures of the investigated samples were significantly modified to lower temperatures with the Cr 3+ content. The frequency characteristics of dielectric properties and impedance spectroscopy had been investigated. The highest dielectric constant ( ε ' ) and resistivity were observed for x = 0.1 and x = 0.2 samples. The complex impedance spectra analysis reveals in-depth information about the conduction mechanism, microstructure, and orientation of the grains in the samples.