Magnetic anisotropy modulation of co-sputtered Fe–SrTiO3 nanocomposite thin films

Nanocomposite thin films that exhibit magnetic anisotropy, in which the direction of the easy axis is perpendicular, are highly desirable for emerging spin-based devices. In this study, the growth behavior and magnetic properties of single-layer Fe thin films sputtered at different temperatures were investigated. The surface morphologies of Fe films dramatically changed when the deposition temperature was varied, and the iron oxide phase was detected in a high-temperature-sputtered film, resulting in the degradation of magnetization and magnetic anisotropy. Then, the microstructures and magnetic properties of the co-sputtered Fe-SrTiO3 nanocomposite thin films were examined. The low-temperate-grown thin films exhibited a flat surface morphology with isotropic magnetic loops at a low power supplied to the Fe target, whereas spherical grains with a strong magnetic anisotropy with in-plane easy axis appeared in a film grown at high power. However, the nanocomposite thin films grown at a high temperature with a higher power for Fe showed perpendicular magnetic anisotropy owing to the vertically aligned Fe rod surrounded by SrTiO3. The modulation of magnetic anisotropy by tuning the geometry and composition of metal–metal-oxide nanocomposites offers a promising approach for the design of future multifunctional devices.