Structural, morphological and frequency dependent dielectric properties of NixZn0.6_xMn0.4Fe2O4 (0.0 < x < 0.4) nanoparticles prepared by sol-gel method

In this work, the spinel ferrite NixZn0.6_xMn0.4Fe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4) nanoparticles (NPs) have been synthesized via the sol-gel method. It is observed that the presence of Ni2+ ions cause an appreciable change in the different properties of the Ni substituted Zn0.6_xMn0.4Fe2O4 NPs. The Fourier transform infrared (FTIR) spectroscopy analysis confirms the formation of the NixZn0.6_xMn0.4Fe2O4 spinel structure. Rietveld's refinement of X-Ray Diffraction (XRD) patterns confirms the single-phase cubic spinel structure belonging to the Fd3m space group. The estimated lattice constant is found to decrease with increasing Ni contents except for x = 0.1 and the average crystallite size varies from 6.7 nm to 100 nm due to the reduction of grain growth upon Ni2+ occupation in the octahedral site. Frequency-dependent dielectric constant, dielectric loss, AC resistivity, and conductivity of the compositions have also been examined at room temperature. The ac resistivity exponentially decreases with the increase of frequency due to the effect of multilayer capacitance. Conversely, the ac conductivity is observed to increase exponentially with the frequency due to increased hopping between metallic cations Fe2+ and Fe3+. The electrical charge conduction behavior and contribution of grain and grain boundary resistance have been explained using Nyquist/Cole-Cole plot. Hence, the Ni doped Zn0.6_xMn0.4Fe2O4 NPs excellent dielectric behavior can be used for various potential applications including the fabrication of the nano-electronic device and multilayers chip inductors applications.