Fabrication, characterization and magnetic behaviour of alumina-doped zinc ferrite nano-particles

摘要

Zinc ferrite nano-powders with a nominal composition of ZnFe_2O_4 were prepared by combustion synthesis using mixture of urea and ammonium nitrate as fuel. The influence of alumina-doping on the structural, morphological and magnetic properties of ZnFe_2O_4 nano-particles was investigated by means of X-ray powder diffraction (XRD), infrared (IR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and vibrating sample magnetometer (VSM). XRD and IR analyses confirm the cubic spinel phase of ZnFe_2O_4 nano-particles. The Zn ferrite presented a uniform microstructure with grain size in nano-scale. Alumina-doping brought about a change in the morphology of the as prepared ferrite from sphere-like to regular hexagon. Al_2O_3-treatment led to a decrease in the coercivity (H_e), magnetization (M_s) and magnetic moment (n_B) of the investigated system. The maximum decrease in the values of H_c, M_s and n_B due to the treatment with 1.5 wt% A1_2O_3 attained 13.5,17.4 and 13.5%, respectively. The observed results can be explained on the basis of particle size and the Fe~(3+) concentration in the octahedral and tetrahedral sites involved in the cubic spinel structure.