Preparation and magnetic properties of magnetite nanoparticles by sol–gel method

 Magnetite (Fe3O4) nanoparticles have been successfully synthesized by sol–gel method combined with annealing under vacuum. The phase structures, morphologies, particle sizes, chemical composition, and magnetic properties of Fe3O4 nanoparticles have been characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectrometer and vibrating sample magnetometer (VSM). The results indicate that the size, the corresponding saturation magnetization value and coercivity value of Fe3O4 nanoparticles increase with the increase of synthesized temperature. And the phase transformation of Fe3O4 nanoparticles has been studied under different atmospheres and temperatures.