Preparation of Nanosized Fe<sub>3</sub>O<sub>4</sub> Powders by Solvothermal Method

Nanosized Fe 3 O 4 particles were prepared in glycol medium through a solvothermal method and the morphologies, structures, surface properties, and magnetism of the samples were characterized by SEM, XRD, FTIR absorption spectra and VSM. The experimental results show that the nanoparticle has a typical diameter of ca. 20 nm. The Fe 3 O 4 nanoparticle diameters increased with increase of PEG content and PEG molecular weight under the case of other unchanged reaction conditions. The XRD pattern confirms that the Fe 3 O 4 nanoparticles belong to cubic structure. The FTIR results indicate that the surface of the Fe 3 O 4 nanoparticles are coated organic matter. Magnetic investigation reveals that the Fe 3 O 4 nanoparticles have higher saturation magnetization and negligible coercivity at room temperature.