Compositional variation of dielectric and magnetic parameters in Ni0.5MgxZn0.5-xFe2O4 spinel ferrites

The ferrite samples Ni0.5MgxZn0.5-xFe2O4; (x = 0.1, 0.2, 0.3 and 0.4) have been synthesized through conventional solid-state reaction procedure. Williamson-Hall Plots suggests micro-strain decreases with increasing Mg content. Microstructure and chemical composition have been studied using Field Emission Scanning Electron Microscope with Energy Dispersive X-Ray Spectroscopy (FESEM-EDX). Dielectric studies have been performed up to 400 °C temperature in the frequency range of 100 Hz to 1 MHz. Dielectric constant as well as tangent loss has been showed dispersive behavior at low frequency region whereas nearly constant behavior at high frequency region. AC conductivity is found to have increasing trend as the frequency increases. The high value of dielectric constant at lower frequencies was possibly due the space charge polarization. The Nyquist plot of impedance shows semi-circular arcs having center lying below the real axis and the radius decreased as temperature increased. Jonscher’s power law (JPL) Fitting has been used to calculate frequency exponent parameter. Saturation magnetization is found to decrease with increasing content of Mg. These ferrites have potent utility in memory devices and transformer core materials.