Single Layers in Two Distinct Regimes*

The advent of skyrmion imaging and electrical detection is an exciting avenue of research as skyrmions hold promise for next-generation magnetic storage. Oxide materials are a great platform to study in this regard owing to their highly tunable properties, pristine epitaxy, and stability. In this talk, I will show Hall detection and real-space imaging of nanoscale skyrmions in perovskite oxide heterostructures of SrIrO₃/SrRuO₃ (SIO/SRO) epitaxial films grown on SrTiO₃(100) substrates. We show regions of large topological Hall resistivity at low temperatures which coincide with the field where the magnetization reverses. Additionally, we present a new high-temperature topological Hall effect not seen before in both bilayer SrIrO₃/SrRuO₃ and single layer SrRuO₃ films. This high temperature phase manifests as a “coercive field switching” in the electrical data and, consequently, as a large topological Hall effect signal. To corroborate our topological Hall signals with skyrmions, we have collected real-space images of isolated skyrmions with low-temperature magnetic force microscopy and show nanoscale skyrmions with diameters as small as 10 nm. Remarkably, the region where skyrmion bubbles are present precisely coincides with the topological Hall peaks. Our results open a platform for tunable nanoscale skyrmions in functional oxide materials.