LIGHT-ENHANCED FERRITE PLATING OF FE3-XMXO4 (M = NI, ZN, CO, AND MN) FILMS IN AN AQUEOUS-SOLUTION

Polycrystalline spinel ferrite films were plated on glass substrates in an aqueous solution by the thin liquid-film method combined with an electric lamp, which was named "light-enhanced ferrite plating." By irradiating the substrate surface with a Xe lamp (450 W/cm2), the deposition rate of Fe3O4 films increased by a factor of approximately 5-10 (from 30 to 150-320 nm/min) compared to that obtained without the light irradiation. The Fe3O4 film prepared in a reaction solution with a small FeCl2 concentration had a structure (i.e., grain size approximately 200 nm, and columnar structure perpendicular to the film surface) similar to that observed when prepared without the light irradiation. However, the grain size increased and the columnar structure disappeared as the FeCl2 concentration increased. The deposition rate of Fe(3-x)Mx)O4 (M = Ni, Mn, Co, and Zn) was 50-100 nm/min and increased by a factor of 2-5 compared to that without the light irradiation. The saturation magnetization of the all films prepared with the light irradiation agrees with the value of the bulk samples.