Evolution of strong second-order magnetic anisotropy in Pt/Co/MgO trilayers by post-annealing

Abstract

In this study, the first- (K-1) and second-order (K-2) magnetic anisotropies are investigated as a function of post-annealing temperature (T-a) in Pt/Co/MgO heterostructures. We find that both extrinsic and intrinsic mechanisms contribute to K-2 with their relative contributions significantly depending on the quality of the Co/MgO interface, which is sensitively affected by the T-a value. In contrast with previous studies that mainly considered the extrinsic effects on K-2, we obtain high K-2 values of up to 2.04x10(6)erg/cm(3) for the stack annealed at T-a = 400 degrees C by maximally utilizing the intrinsic effect at the Co/MgO interface, thus facilitating robust easy-cone anisotropy. We also demonstrate that the canted magnetization can be efficiently manipulated by the spin-orbit torques generated from the Pt layer, which is an important step toward the application of easy-cone states in various spintronic devices.