Structural, microstructural, magnetic and dielectric properties of Ni-Zn ferrite powders synthesized by plasma arc discharge process followed by post-annealing

In this work, Ni_0.5Zn_0.5Fe₂O₄ powders were prepared by plasma arc discharge method followed by the subsequent heat treatments within the temperature range of 1000–1250 °C. Structural, microstructural, magnetic and dielectric properties of the as-synthesized and heat treated powders are examined in detail. The results indicate that as-synthesized powders contain a mixture of ZnO, Fe₀.₇₂OZn_0.13 and Ni-Zn ferrite phases. However, the quantitative amount of Ni-Zn ferrite phase gradually increases by post annealing process. This finding is accompanied by an improvement in the magnetic properties such that a single phase Ni-Zn ferrite with the average crystallite size of 212 nm, lattice parameter of 8.332 Å, saturation magnetization of 35.1 emu/g and coercivity of 24.9 Oe is formed after annealing at 1250 °C. Nevertheless, dielectric properties measured in the frequency range 20 Hz–10 MHz exhibits a complex behaviour due to the different mechanisms that cause polarization.