Spinel structure ferrites MFe2O4(M = Co,Ni,Mn,Zn) nano-octahedrons have been fabricated by a simple hydrothermal route under mild conditions,using sodium citrate as addition agent.The products were characterized in detail by XRD,TEM and ED.The growth process was also monitored by NaOH concentration,temperature and citrate-dependent observations.It was found that the reaction temperature had no obvious influence on the morphology of the products,while NaOH concentration had great effect on the morphology of the final products.The edge size of octahedral ferrites was estimated to 100-200 nm at the hydrothermal temperature of 180 ℃.Vibrating sample magnetometer was used to characterize magnetic properties of octahedral ferrites at room temperature.Magnetic measurements showed that these ferrites exhibited obvious ferromagnetic behaviors.
