In-plane Broken Symmetry with Strong Perpendicular Magnetization in Ru-substituted Manganite Films*

Understanding the origin of magnetic anisotropy provides insights into the interplay of various factors, including crystal symmetry, spin-orbit coupling, and exchange interactions, thereby playing a crucial role in designing the required magnetic materials for various applications. Recent studies on the Ru substituted La_0.70Sr_0.30MnO₃ (Ru-LSMO) films have illustrated non-trivial magnetic topologies, and enhanced anomalous Hall effect, where tilted magnetic anisotropy (TMA) plays a crucial role. While perpendicular magnetization has been demonstrated with Ru-LSMO, anisotropic in-plane magnetization was not addressed. Here we describe anisotropic in-plane magnetization coexisting with strong perpendicular magnetization in 10% Ru substituted LSMO films with Curie temperature near room temperature. In our recent work, we unveil a monoclinic, fully-strained phase, and 1D periodic in-plane structural domains. We determine that the in-plane symmetry breaking by the monoclinic crystal structure induces weekly anisotropic in-plane magnetization, which is further enhanced by the 1D periodic structural modulation. We further illustrate how the interplay of in-plane crystal symmetry breaking, octahedral rotation, spin-orbit coupling, and the magnetic interaction between Ru and Mn ions induce such a complex TMA. Such TMA is attractive for cutting edge spintronic memories such as spin-orbit-torque based deterministic perpendicular magnetization switching.