Evolution from (110) Fe to (111) Fe3O4 thin films grown by magnetron sputtering using Fe2O3 target

Fe and Fe3O4 thin films were grown by radio frequency magnetron sputtering. Fe2O3 was used as the target and hydrogen was introduced together with Argon gas to provide a certain reducing atmosphere. By varying H2/Ar flow ratio, the changes in composition and structure of the thin films from (110) Fe to (111) Fe3O4 were observed by X-ray diffraction. The valence states of Fe in the thin films were analyzed by X-ray photoelectron spectroscopy. Magnetization measurements indicate that the Fe thin films grown with low H2/Ar flow ratios possess large coercive force. It was ascribed to the increasing boundary density and the increasing amount of Fe oxides such as FeO distributed at the boundary.

► (110) Fe and (111) Fe3O4 thin films were grown by magnetron sputtering with Fe2O3 target.
► H2 was introduced to provide a reducing ambient.
► The coercive force of Fe thin films increases with the decreasing H2/Ar flux ratio.