2016/07/26 by J. Matsuno, N. Ogawa, K. Yasuda +5 · 3 citations
Physics and Astronomy · #cond-mat.str-el #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1126/sciadv.1600304
published as Sci. Adv. 2, e1600304 (2016) · 18 pages, 3 figures; revised version has been published in Sci. Adv. 2, e1600304 (2016)
arxiv created 2016/07/26 · arxiv updated 2016/07/27
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 SrRuO3 and paramagnetic SrIrO3 over a wide region of both temperature and magnetic field. The topological term rapidly decreases with the thickness of SrRuO3, ending up with the complete disappearance at 7 unit cells of SrRuO3. 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 SrIrO3. Such interaction is expected to realize the Néel-type magnetic skyrmion, of which size is estimated to be ∼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.