Synthesis and Characterization of MnZn Ferrite Nanoparticles with Improved Saturation Magnetization

Abstract

Mn0.8Zn0.2Fe2O4 nanoparticles with improved saturation magnetization were prepared by a modified hydrothermal method. This method involves a chemical co-precipitation of hydroxides under a vacuum condition using potassium hydroxide as a precipitating agent, followed by a separate hydrothermal process. To understand the advantages of the modified hydrothermal method proposed above, a sample having identical stoichiometry was prepared by conventional hydrothermal method, during which the preparation of precursor was conducted in an open system. The samples were characterized by XRD, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and TEM. The magnetic property was tested by vibrating sample magnetometer (VSM). XPS results show that the Mn cations of the nanoparticles prepared by modified hydrothermal method have lower average valence. The MnZn ferrite nanoparticles prepared by modified hydrothermal method have smaller diameter (16.1 nm, calculated by XRD) and higher room temperature saturation magnetization, 80 emu/g, which is even better than the reported value. The saturation magnetization of the particles prepared by modified hydrothermal method is 1.6 times of the particles prepared by conventional hydrothermal method.