Magnetic anisotropy and planar topological Hall effect in SrMn_xIr_1-x O₃films

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_xIr_1-xO₃thin films, having both 3dand 5delements on the perovskiteBsites. 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 Mne_gelectrons preferentially occupy thed3z2-r2orbital, which produces the observed PMA in the framework of spin-orbital coupling. A planar topological Hall effect appears in SrMn_xIr_1-xO₃films withxabout 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.