Spin-Hall topological Hall effect in highly tunable Pt/ferrimagnetic-insulator bilayers

Electrical detection of topological magnetic textures such as skyrmions has been limited to conducting materials. Magnetic insulators offer key advantages for skyrmion technologies with high speed and low loss. We observe a prominent topological Hall effect in Pt/Tm₃Fe₅O₁₂ bilayers, where the pristine Tm₃Fe₅O₁₂ epitaxial films down to 1.25 unit cell thickness allow for tuning of topological Hall stability over a broad range from 200 to 465 K through atomic-scale thickness control [1]. Although Tm₃Fe₅O₁₂ is insulating, the topological magnetic textures can be detected through a novel phenomenon: “spin-Hall topological Hall effect” (SH-THE), where the interfacial spin-orbit torques allow spin-Hall-effect generated spins in Pt to experience the unique topology of the underlying skyrmions in Tm₃Fe₅O₁₂. This novel electrical detection phenomenon paves a new path for utilizing a large family of magnetic insulators in future skyrmion technologies.
[1]. A. S. Ahmed, A. J. Lee, N. Bagués, B. A. McCullian, A. M. A. Thabt, A. Perrine, P.-K. Wu, J. R. Rowland, M. Randeria, P. C. Hammel, D. W. McComb, and F.. Y. Yang, “Spin-Hall topological Hall effect in highly tunable Pt/ferrimagnetic-insulator bilayers,” Nano Lett., 19, 5683 (2019).