講演情報
[8p-E208-12]Tuning Spin-Orbit Torque Switching through Strain-controlled Octahedral Rotation in Single-Layer SrRuO3
〇(D)Hiroto Horiuchi1, Yi Jeyoung1, Wakabayashi Yuki K.2, Sato Yukio3, Kunihashi Yoji2, Kcrockenberger Yoshiharu2, Tanaka Masaaki1,4,5, Ohya Shinobu1,4,5 (1.EEIS, UTokyo, 2.BRL, NTT, Inc., 3.Kumamoto Univ., 4.CSRN, UTokyo, 5.Nano Quine, UTokyo)
キーワード：
spin-orbit torque、epitaxial strain、oxide electronics
SrRuO3 (SRO) is a promising spin-orbit torque (SOT) source owing to its strong spin Berry curvature (SBC) from band crossings, and its compatibility with perovskite oxide heterostructures enables all-oxide spintronics. We previously demonstrated current-induced SOT magnetization switching in a fully epitaxial SRO single layer on lattice-matched SrTiO3 (STO), where an inhomogeneous oxygen octahedral rotation (OOR), pronounced a few nm from the interface, breaks inversion symmetry and enhances SBC via band modulation. Because OOR couples to substrate strain, the switching efficiency should be tunable by strain engineering. Here we prepared SRO/NdGaO3 (NGO), where NGO imposes ~1.7% compressive strain. The film shows a rectangular anomalous Hall loop, indicating strong perpendicular anisotropy, and exhibits single-layer current-induced switching. The large compressive strain suppresses OOR propagation into the interior, confining it within a few nm of the interface; this interface-confined inversion-symmetry breaking likely drives the switching. The larger switching current density (~107 A cm-2) than SRO/STO indicates that the spatial extent of OOR critically governs SOT efficiency. Substrate-strain engineering thus offers an effective route to tune SOT switching in single-crystalline oxide ferromagnets.