Prepare highly crystalline NiFe2O4 nanoparticles with improved magnetic properties

Hydrothermal process was successfully used to synthesize NiFe2O4 powder using ferric chloride (FeCl3) and nickel chloride (NiCl2.4H(2)O) as starting materials by carefully controlling the reaction conditions. The as-prepared NiFe2O4 sample was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), Mossbauer spectra and its magnetic properties were evaluated on a vibrating sample magnetometer (VSM). The nanoscale (25 nm) NiFe2O4 powder obtained at 140 degrees C for 12 h possessed a saturation magnetization of 53.6 emu/g, close to that of the correspondent bulk materials. It is suggested that the well-crystallized NiFe2O4 particles formed under appropriate hydrothermal conditions should be responsible for the increased saturation magnetization in nanosized NiFe2O4. (c) 2005 Elsevier B.V. All rights reserved.