Structure and magnetic properties correlated with cation distribution of Ni0.5-xMoxZn0.5Fe2O4 ferrites prepared by sol-gel auto-combustion method

Abstract

The Ni0.5-xMoxZn0.5Fe2O4 (x = 0.00, 0.005, 0.01, 0.015 and 0.02) ferrites have been synthesized by the sol-gel auto-combustion method. The crystal structure, surface morphology, magnetic properties, and cation distribution of the ferrites have been investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). The lattice parameter initially decreases and then sharply increases. According to the analysis of SEM and magnetic properties, there is the second phase NiO existing in the sample of x = 0.02. Cation distribution estimated from XRD, SEM and magnetic properties analyses suggests that Mo6+ ions occupy the tetrahedral sites, and more and more Fe2+ ions appear in the samples with the addition of Mo content. The saturation magnetization (Ms) and initial permeability (μi) of samples increase firstly, and then sharply decrease with increasing Mo6+ content from x = 0.005 to x = 0.02. The Ni0.485Zn0.5Mo0.015Fe2O4 ferrite has the maximum Ms of 82.2 emu/g and μi of 86. Meanwhile, it presents the best microstructure, the largest bulk density and the lowest porosity.