Hydrothermal growth of octahedral Fe3O4 crystals

This paper reports the growth of octahedral magnetic Fe₃O₄ particles from iron powders via a simple alkaline hydrothermal process. The chemical compositions and morphologies of the as-grown Fe₃O₄ particles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), and scanning electron microscopy (SEM). Structure characterization showed that the phase structure of the prepared particles evolved from α-Fe to pure Fe₃O₄ with increasing concentration of KOH, indicating the important role of KOH concentration on the formation of the magnetite octahedron. The magnetic properties of samples were also studied by means of a vibrating sample magnetometer (VSM). The pure magnetite Fe₃O₄ octahedrons exhibited a relatively high saturation magnetization of 96.7 emu/g.