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arXiv · 1607.07536

Interface-driven topological Hall effect in SrRuO$_3$-SrIrO$_3$ bilayer

J. Matsuno·N. Ogawa·K. Yasuda·F. Kagawa·W. Koshibae·N. Nagaosa·Y. Tokura·M. Kawasaki
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Abstract

Electron transport coupled with magnetism has attracted attention over the years as exemplified in anomalous Hall effect due to a Berry phase in momentum space. Another type of unconventional Hall effect -- topological Hall effect, originating from the real-space Berry phase, has recently become of great importance in the context of magnetic skyrmions. We have observed topological Hall effect in bilayers consisting of ferromagnetic SrRuO$_3$ and paramagnetic SrIrO$_3$ over a wide region of both temperature and magnetic field. The topological term rapidly decreases with the thickness of SrRuO$_3$, ending up with the complete disappearance at 7 unit cells of SrRuO$_3$. Combined with model calculation, we concluded that the topological Hall effect is driven by interface Dzyaloshinskii-Moriya interaction, which is caused by both the broken inversion symmetry and the strong spin-orbit coupling of SrIrO$_3$. Such interaction is expected to realize the N\'{e}el-type magnetic skyrmion, of which size is estimated to be $\sim$10 nm from the magnitude of topological Hall resistivity. The results established that the high-quality oxide interface enables us to tune the chirality of the system; this can be a step towards the future topological electronics.

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J. Matsuno, N. Ogawa, K. Yasuda, F. Kagawa, W. Koshibae, N. Nagaosa, Y. Tokura, M. Kawasaki. 2016-07-26. Interface-driven topological Hall effect in SrRuO$_3$-SrIrO$_3$ bilayer. https://doi.org/10.1126/sciadv.1600304

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