Interfacial tuning of chiral magnetic interactions for large topological Hall effects in LaMnO3/SrIrO3 heterostructures*

One of the most intriguing outcomes of symmetry breaking and spin-obit interactions in magnetic systems is the possibility to create non-collinear and chiral spin textures. The Dzyaloshinskii-Moriya interaction (DMI) results from strong spin-orbit coupling and broken inversion symmetry to generate magnetization rotations with fixed chirality. The discovery of magnetic skyrmions originating from strong DMI in metal thin films has led to an explosion of efforts to manipulate magnetic phases originating from interfaces. We have studied interface-induced magnetism in epitaxial 3d/5d iridate/manganite superlattices. In LaMnO₃/SrIrO₃ superlattices, we find a large additional topological Hall effect arising from the interaction of charge carriers with a noncoplanar chiral spin texture induced by interfacial DMI[1]. I will describe how the interfacial atomic layer stacking and symmetry enabled by the nonmagnetic A-sites determine the competition between collinear and chiral magnetic interactions originating from the oxide interface. Our findings [2] provide insight to the manipulation of chiral magnetism from atomic-scale control of exchange interactions at oxide interfaces.
References: [1] P. Bruno et al., Phys. Rev. Lett. 93, 096806 (2004). [2] E. Skoropata et al., Sci. Adv., 6, eeaz3902 (2020).