抄録
Submicrometer-sized spheres of iron oxide were obtained by laser irradiation of cuboidal Fe3O4 particles dispersed in ethanol, acetone, and toluene. Sphere formation condition and sphere size are explained based on a relationship between particle size and laser fluence required for solid-liquid phase transition of Fe3O4, which is calculated by equating the melting enthalpy and the optically absorbed energy derived from Mie theory. FeO was partially formed by laser irradiation at 200 mJ pulse-1 cm-2 in ethanol, acetone and toluene. The reduction reaction is not simply due to thermal decomposition of Fe3O4, but due to the reduction by chemical species generated from solvent surrounding Fe3O4 particles melted by laser irradiation. Ethanol was more reductive than the other two solvents; Fe is formed even at 200 mJ pulse-1 cm-2. This is probably due to chemical rectivity of produced iron oxides and chemical species transiently generated from solvent.
