Influence of Zn²⁺ doping towards the structural, magnetic, and dielectric properties of NiFe₂O₄ composite

The present work is aimed to study the changes in characteristics of nickel ferrites followed by the zinc doping and for that, the nanocrystalline Ni–Zn ferrites (Ni_1−xZn_xFe₂O₄: x = 0, x = 0.2 and x = 0.4) were prepared via sol–gel auto combustion method and by annealing at subsequent temperature. The physical characterization studies of the final composite provided that the lattice structure of Zn²⁺ substituted at Ni sites confirms for the single-phase ferrite with spinel structure got investigated at room temperature (RT) with functional, morphological as well as temperature-dependent magnetic and dielectric properties. The magnetic properties imply that the distribution of cations at the lattice sites suggests that the magnetization is getting increased with a decrease of temperature from RT to lower temperature in a field cooling process and is due to the strong dipolar magnetostatic interactions between the individual magnetic moments, which also affirms that the magnetization decreases with a decrease of Ni concentration. The coercively extracted from isothermal magnetization curves attributed to the single domain nature at RT. Further, the dielectric constant (ε′) and dielectric loss (tan δ) are also examined and found to be strongly dependent on the function of frequency and temperature. The change in ε′ and tan δ demonstrated that the dispersion due to the Maxwell–Wagner interfacial polarization and is in a good agreement with Koop's theory.