Synthesis and Characterization of Superparamagnetic Fe<sub>3</sub>O<sub>4</sub> Nanoparticles

We synthesized Fe 3 O 4 nanoparticles using a solvent thermal method and characterized the morphologies, structures, surface properties, thermal stability and magnetism of the products by Field emission scanning electron microscopy (FE-SEM), Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The experimental results showed that the Fe 3 O 4 nanoparticles have a tunable average size range from 55 nm to 85 nm. Their diameters decreased with increase of precursor FeCl 2 4H 2 O concentration or increase of the reaction time under other reaction conditions held constant. The XRD pattern confirmed that the Fe 3 O 4 nanoparticles belong to cubic structure. Magnetic investigation reveals that the Fe 3 O 4 nanoparticles have higher saturation magnetization and negligible coercivity at room temperature.