Controlling the crystallographic orientation and easy axis of magnetic anisotropy in L10 FePt films with Cu additive

By co-sputtering Cu and FePt onto Cr90Mo10 underlayers, the preferred orientation and easy axis of magnetic anisotropy of FePt films were successfully changed from the perpendicular to the in-plane direction. The pure FePt film grown on the Cr90Mo10 underlayer showed a (001) preferred orientation with out-of-plane magnetic anisotropy. As 20 and 40 vol.% Cu were doped, the FePt films showed a (200) preferred orientation with in-plane magnetic anisotropy. The pure FePt film showed a continuous microstructure, while the Cu-doped FePt films showed a mixture of particle-like and continuous microstructures. The change of the preferred orientation in the FePt films by Cu doping might be due to the competition of grain-boundary energy, surface free energy and epitaxial-strain energy. The experimental results suggest that the Cu doping be a promising method for the fabrication of the in-plane oriented FePt films. The Cu-doped FePt films had a lower Ms than the pure FePt film.