Characterization of Spinel-Structured Iron Oxide Particles Synthesized by Heating α-Fe₂O₃ Platelets in Tetra-Ethylene Glycol

抄録

Platelet particles of α-Fe₂O₃ 30–50 nm in size were heated in tetra-ethylene glycol to obtain spinel-structured iron oxide particles, which were confirmed by X-ray diffraction. With heating, 100 nm platelets were formed, and the proportion of the 100 nm platelets increased in comparison to 30–50 nm platelets with increasing duration of heating. In all the samples, irrespective of the heating time used during synthesis, the coercive force, which was considered to be dependent on the shape anisotropy of the platelet particles, remained nearly constant at 12.7–13.5 kA/m (160–170 Oe). The saturation magnetization initially increased and then decreased with the heating time and the maximum value observed was 80.5 Am²/kg (80.5 emu/g). The reduction and oxidation were considered to occur simultaneously during the synthesis.