Magnetic anisotropy and planar topological Hall effect in SrMn _x Ir_{1- x} O₃ films

Strong Coulomb repulsion and spin-orbit coupling are known to give rise to exotic physical phenomena in transition metal oxides. Here, we report magnetic and transport characteristics of (001) oriented epitaxial SrMn (x) Ir1-x O3 thin films, having both 3d and 5d elements on the perovskite B sites. With the increase of Mn concentration, perpendicular magnetic anisotropy (PMA) decreases gradually in accompany with the magnetic easy axis tilting away from the out-of-plane [001] direction. X-ray absorption spectroscopy reveals that Mn e (g) electrons preferentially occupy the d3z2-r2 x Ir1-x O3 films with x about 0.30 when the magnetic field is applied along the current, which is a result of the noncoplanar spin structure due to the competition among the PMA, the magnetic exchange interaction and the Zeeman energy. These results provide an example to show the subtle balance among complex competitions in materials with both strong correlation and spin-orbit coupling.