Cooperative control of perpendicular magnetic anisotropy via crystal structure and orientation in freestanding SrRuO3 membranes

Flexible magnetic materials with robust and controllable perpendicular magnetic anisotropy (PMA) are highly desirable for developing flexible high-performance spintronic devices. However, it is still challenge to fabricate PMA films on polymers directly. Here, we report a facile method for synthesizing single-crystal freestanding SrRuO3 membranes with controlled crystal structure and orientation using water-soluble Ca3-xSrxAl2O6 sacrificial layers. Through cooperative effect of crystal structure and orientation, flexible membranes reveal highly tunable magnetic anisotropy from in-plane to out-of-plane with a remarkable PMA energy of 7 × 106 erg·cm−3. First-principle calculations reveal that the underlying mechanism of PMA modulation is intimately correlated with structure-controlled Ru 4d-orbital occupation, as well as spin-orbital matrix element differences, dependent on the crystal orientation. In addition, even after 10,000 bending cycles, the PMA keeps stable, indicating a robust magnetism reliability in the prepared films. This work provides a feasible approach to prepare the flexible oxide films with strong and controllable PMA.