  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.
