Tuning Perpendicular Magnetic Anisotropy by Oxygen Octahedral Rotations in (La$_{1-x}$Sr$_{x}$MnO$_{3}$)/(SrIrO$_{3}$) Superlattices

Perpendicular magnetic anisotropy (PMA) plays a critical role in the development of spintronics, thereby demanding new strategies to control PMA. Here we demonstrate a conceptually new type of interface induced PMA that is controlled by oxygen octahedral rotation. In superlattices comprised of La$_{1-x}$Sr$_{x}$MnO$_{3}$ and SrIrO$_{3}$, we find that all superlattices (0$\leq$x$\leq$1) exhibit ferromagnetism despite the fact that La$_{1-x}$Sr$_{x}$MnO$_{3}$ is antiferromagnetic for x$>$0.5. PMA as high as 4$\times$10$^6$ erg/cm$^3$ is observed by increasing x and attributed to a decrease of oxygen octahedral rotation at interfaces. We also demonstrate that oxygen octahedral deformation cannot explain the trend in PMA. These results reveal a new degree of freedom to control PMA, enabling discovery of emergent magnetic textures and topological phenomena.