Preparation and Characterization of Monodispersed Fe3O4 Sub-microspheres

Size-controllable, better dispersed, hydrophilic and superparamagnetic submicron Fe3O4 spheres were perpared by a solyotherrnal method. Effects of surfactants, reaction time and reaction temperature on the product were examined. XRD, FTIR, FE-SEM, and superconducting quantum interface device (SQUID) were employed to characterize the Fe3O4 microspheres. The results show that Fe3O4 microshperes have a cubic structure and better dispersibility, the sizes of Fe3O4 microshperes can be controlled at 140 similar to 360 nm, the samples are superparamagnetic at room temperature and the coercivity is negligible. The surfactants have an influence on the size and saturation magnetization of the samples but have no effect on the crystalline phase structure and morphologies. With the increasing of reaction time and temperature, the size of the samples decreases.