Synthesis of Fe3O4 Nanoparticles and their Magnetic Properties

Fe3O4 magnetic nanoparticles (MNPs) were synthesized by a co-precipitation method using sodium citrate and oleic acid as modifiers. Phase composition and microstructure analysis indicate that the sodium citrate and oleic acid have been successfully grafted onto the surface of Fe3O4 MNPs. The magnetic behaviors reveal that the modification can decrease the saturation magnetization of Fe3O4 MNPs due to the surface effect. Fe3O4 MNPs modified by sodiumcitrate and oleic acid show excellent dispersion capability, which should be ascribed to the great reduction of high surface energy and dipolar attraction of the nanoparticles.