Hydrothermal Synthesis and Magnetic Properties of Fe₃O₄ Octahedral Microcrystals

Abstract

Magnetite Fe3O4 octahedral microcrystals have been successfully synthesized from K4 [Fe (CN)6] and NaOH reagents via a simple hydrothermal process. The morphology and structure of products were characterized by XRD, SEM, and TEM. Magnetic property was detected by a vibrating sample magnetometer at room temperature. The results showed that the prepared Fe3O4 octahedral microcrystals were single crystals with face-center cubic structure and a size distribution from 0.5 to 1.0 μm. The octahedral microcrystals exhibited a ferromagnetic behavior with the coercive force (Hc), saturation magnetization (Ms), and remanent magnetization (Mr) of 70.02 Oe, 71.57 emu/g, and 4.90 emu/g, respectively. It was also found that the NaOH solution and reaction temperature had an important effect on the formation of Fe3O4 octahedra. A possible mechanism was proposed to account for the growth of Fe3O4 octahedra.