Polycrystalline Fe3O4 films were plated on glass substrates in an aqueous solution. By irradiating the substrate surface with an Xe lamp at power density of ~450 W/cm2, the deposition rate of Fe3O4 film was increased by a factor of about 10 (from ~30 nm/min to ~320 nm/min). With light irradiation times as short as 4 min, we obtained ferrite films of ~2 Â¿m thickness. We believe that the light accelerates the reaction by raising the temperature. X-ray analysis revealed that the films were polycrystalline with a spinel structure, with no preferred orientation, and no scattering due to impurity phases was observed.