Spin-Hall Topological Hall Effect in Highly Tunable Pt/Ferrimagnetic-Insulator Bilayers
Fengyuan Yang, Ohio State University
April 10, 2020
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. Prof. Yang and collaborators reported 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, 2]. Although Tm3Fe5O12 is insulating, they demonstrate the detection of topological magnetic textures 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.
 Adam S. Ahmed, Aidan J. Lee, Nuria Bagués, Brendan A. McCullian, Ahmed M. A. Thabt, Avery Perrine, Po-Kuan Wu, James R. Rowland, Mohit Randeria, P. Chris Hammel, David W. McComb, and Fengyuan Yang, Spin-Hall topological Hall effect in highly tunable Pt/ferrimagnetic-insulator bilayers, Nano Letters 19, 5683 (2019).
 A. J. Lee, A. S. Ahmed, J. Flores, S. D. Guo, B. B. Wang, N. Bagués, D. W. McComb, and F. Y. Yang, Probing the Source of Interfacial Dzyaloshinskii-Moriya interaction Responsible for Topological Spin Textures in Metal/Tm3Fe5O12 Systems, Phys. Rev. Lett. 124, 107201 (2020).