Engineering of octahedral rotation and magnetic anisotropy in LaCrO₃/LaMnO₃ superlattice

As the magnetic anisotropy (MA) has become important for high performance spintronics applications, developing an effective way to control MA in magnetic system has been of great interest. The magnetic properties of perovskite transition-metal oxides are highly tunable with thin film deposition techniques such as molecular beam epitaxy (MBE) and thus provide a fascinating playground to manipulate MA. While the interface effect and strain in the perovskite thin film/superlattice has been widely investigated to tune the MA, open questions remain related to the effect oxygen vacancy on MA. Here, we studied the magnetic anisotropy and oxygen octahedral rotation of MBE grown LaCrO₃/LaMnO₃(LCO/LMO) superlattices with different oxygen vacancy concentrations. The atomic-scale structure analyzation based on high-resolution synchrotron X-ray diffraction indicates differences in the oxygen octahedral rotation configuration of the LCO/LMO superlattice before and after annealing in oxygen. The antiferromagnetic coupling between Mn and Cr is verified by X-ray magnetic circular dichroism measurements. The angular dependent magnetism of LCO/LMO superlattice is investigated by SQUID measurement and shows a changes in the magnetic anisotropy which are correlated with the oxygen-vacancy induced structural transitions. Our finding leads to a better understanding of microscopic origin of the magnetic anisotropy in LCO/LMO superlattices and demonstrates a pathway to engineer the magnetic anisotropy with oxygen vacancy in transition-metal oxide heterostructures.