Magnetic properties of bismuth substituted yttrium iron garnet film with perpendicular magnetic anisotropy

In this paper, the Y2Bi1Fe5O12 films were grown on substituted gadolinium gallium garnet substrate by radio frequency magnetron sputtering and their magnetic properties were investigated. We found that the 20 nm-thick film had the best perpendicular magnetic anisotropy (PMA) under the combined effect of stress-induced anisotropy and surface roughness of the film; the applied magnetic field required for its out-of-plane magnetization saturation was 90 Oe, the remanence ratio was 0.8, the coercive force was 30 Oe, and the damping constant was 3.37 × 10−3. The PMA of the films was reduced due to the relaxation of the stress as the thickness of the film increased, and the easy magnetization axis became in-plane as the thickness reached 40 nm.