Preparation and Magnetic Properties of MnFe2O4 Octahedral Microcrystals

MnFe2O4 octahedra have been prepared by reaction of Mn2+ ions and Fe3+ in alkaline condition via heat treatment of the coprecipitation product. The as-prepared powders were characterized in detail by conventional techniques such as powder x-ray diffraction; field emission electron microscopy and transmission electron microscopy. Vibrating sample magnetometer was used to determine the magnetic properties at room temperature. The results show that the MnFe2O4 octahedra were single crystals with cubic jacobsite structure and a size distribution from 0.8 to 1.0 μm. The octahedra obtained at 1100 and 1200 °C exhibited a ferromagnetic behavior with the coercive force (Hc) value of 49.03 and 39.23 Oe, saturation magnetization (Ms) value of 42.93 and 47.98 emu/g and remanent magnetization (Mr) value of 2.16 and 2.55 emu/g, respectively. It is indicated that the heat treatment temperature has a significant effect on the formation of the jacobsite structure. Furthermore, a possible mechanism was also proposed to account for the growth of these products.