The magnetite (Fe₃O₄) nanoparticles were successfully synthesized and annealed under vacuum at different temperature. The Fe₃O₄ nanoparticles prepared via sol-gel assisted method and annealed at 200–400 °C were characterized by Fourier Transformation Infrared Spectroscopy (FTIR), X-ray Diffraction spectra (XRD), Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscopy (AFM). The XRD result indicate the presence of Fe₃O₄ nanoparticles, and the Scherer’s Formula calculated the mean particles size in range of 2–2.5 nm. The FESEM result shows that the morphologies of the particles annealed at 400 °C are more spherical and partially agglomerated, while the EDS result indicates the presence of Fe₃O₄ by showing Fe–O group of elements. AFM analyzed the 3D and roughness of the sample; the Fe₃O₄ nanoparticles have a minimum diameter of 79.04 nm, which is in agreement with FESEM result. In many cases, the synthesis of Fe₃O₄ nanoparticles using FeCl₃ and FeCl₂ has not been achieved, according to some literatures, but this research was able to obtained Fe₃O₄ nanoparticles base on the characterization results.
