Preparation and Magnetic Properties of Ni0.36Zn0.64 Ferrite from Microwave-Induced Combustion

Abstract

Ni–Zn ferrite powders were successfully synthesized using microwave induced combustion. The process took only 15 min to obtain as-received Ni–Zn ferrite powders. The resultant powders were annealed at different temperatures and were investigated by differential thermal analysis/thermogravimetry (TG/DTA), X-ray diffractometry (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The as-received powders showed the formation of cubic ferrite with saturation magnetization (Ms) of 23 emu/g and an intrinsic coercive force (Hc) of 135 Oe, whereas upon annealing at 850°C for 2 h, the saturation magnetization increases to 58 emu/g and the intrinsic coercive force reached 197 Oe. The toroidal specimen sintered at 1200°C for 2 h presented both an optimum initial permeability (µi) and quality factor (Q). The high initial permeability and large quality factor were closely associated with effective improvement of the densification and magnetic characteristics properties of sintered specimen made from nanosized Ni–Zn ferrite powder prepared by microwave-induced combustion.