Angular dependence of Hall effect and magnetoresistance in SrRuO3-SrIrO3 heterostructures

The perovskite SrRuO3 is a prototypical itinerant ferromagnet which allows interface engineering of its electronic and magnetic properties. We report the synthesis and investigation of atomically flat artificial multilayers of SrRuO3 with the spin-orbit semimetal SrIrO3 in combination with band-structure calculations with a Hubbard U term and topological analysis. The latter reveal an electronic reconstruction and emergence of flat Ru-4d(xz) bands near the interface, ferromagnetic interlayer coupling, and a negative Berry-curvature contribution to the anomalous Hall effect. We analyze the Hall effect and magnetoresistance measurements as a function of the field angle from an out-of-plane towards an in-plane orientation (either parallel or perpendicular to the current direction) by a two-channel model. The magnetic easy direction is tilted by about 20 degrees from the sample normal for low magnetic fields, rotating towards the out-of-plane direction by increasing fields. Fully strained epitaxial growth enables a strong anisotropy of magnetoresistance. An additional Hall effect contribution, not accounted for by the two-channel model, is compatible with stable skyrmions only up to a critical angle of roughly 45 degrees from the sample normal. Within about 20 degrees from the thin film plane an additional peaklike contribution to the Hall effect suggests the formation of a nontrivial spin structure.

Automated summary

Synthesis and investigation of artificial multilayers of SrRuO3 with SrIrO3 revealed electronic reconstruction, ferromagnetic interlayer coupling, and a negative Berry-curvature contribution to the anomalous Hall effect. The magnetic easy direction rotates with increasing fields, resulting in strong anisotropy of magnetoresistance.