Effect of Reaction Temperature on Particle Size of Iron Oxide Nanoparticles via Heating of Platelet <inline-formula> <tex-math notation="LaTeX">${\alpha }$ </tex-math></inline-formula>-FeOOH in Tetraethylene Glycol

Abstract

We investigated the effect of reaction temperature on particle size of spinel-structured ferromagnetic iron oxide particles obtained by heating the platelet $\alpha $ -FeOOH particles in tetraethylene glycol (TEG). This method is advantageous as it enables the omission of outer SiO2 shell layer and makes the surface modification easier. Oxide samples were reduced from $\alpha $ -FeOOH particles using TEG. The Fe3O4 particles were obtained through the formation of $\alpha $ -Fe2O3. The particles with single-phase Fe3O4 were obtained by heating above the temperature of 290 °C and confirmed by X-ray diffraction and Mossbauer spectroscopy. Among these single-phase Fe3O4 particles, a large proportion of relatively small-sized particles was obtained by increasing the reaction temperature to 310 °C. Fe3O4 particles sized 30–80 nm were finally obtained after heating at 310 °C for 60 min with the saturation magnetization of 83 Am2/kg and a coercive force of 13 kA/m.