One-step hydrothermal process to prepare highly crystalline Fe 3O 4 nanoparticles with improved magnetic properties

Abstract

Hydrothermal process was successfully used to synthesize Fe 3O 4 powder using ferrous chloride (FeCl 2) and diamine hydrate (H 4N 2·H 2O) as starting materials by carefully controlling the reaction conditions. The as-prepared Fe 3O 4 sample was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and its magnetic properties were evaluated on a vibrating sample magnetometer (VSM). The nanoscale (40 nm) Fe 3O 4 powder obtained at 140 °C for 6 h possessed a saturation magnetization of 85.8 emu/g, a little lower than that of the correspondent bulk Fe 3O 4 (92 emu/g). It is suggested that the well-crystallized Fe 3O 4 grains formed under appropriate hydrothermal conditions should be responsible for the increased saturation magnetization in nanosized Fe 3O 4.