Spin-orbit torque study on MBE-grown Bi<sub>1-x</sub>Sb<sub>x</sub> thin films

ORAL

Abstract

Strong spin-orbit torque (SOT) generated by the surface and bulk states in topological insulator (TI)/ferromagnet heterostructures offers new opportunities in thin film magnetization manipulation for low power-consumption magnetoresistive random-access memory devices. The Bi1-xSbx alloy system has recently attracted interest in this context because of energy-efficient SOT switching [Nature Mater. 17, 808 (2018)]. This motivated us to study current-induced SOT in thin film Bi1-xSbx/ferromagnet heterostructures via spin-torque ferromagnetic resonance (ST-FMR). We briefly describe the synthesis by molecular beam epitaxy of Bi1-xSbx thin films and their characterization via reflection high energy diffraction, x-ray diffraction, transmission electron spectroscopy, and in vacuo angle-resolved photoemission spectroscopy. We then discuss the ST-FMR measurement of SOT at room temperature in Bi1-xSbx thin films as we vary the composition within and outside the topological regime.

*Supported by the Penn State 2DCC-MIP under NSF Grant No. DMR-2039351 and by SMART, one of seven centers of nCORE, a Semiconductor Research Corporation program, sponsored by the National Institute of Standards and Technology (NIST).

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Presenters

  • Yongxi Ou

    • Pennsylvania State University

Authors

  • Yongxi Ou

    • Pennsylvania State University

  • Wilson J Yanez

    • Pennsylvania State University

  • Yu-Sheng Huang

    • Pennsylvania State University

  • Supriya Ghosh

    • University of Minnesota

  • Max C Stanley

    • Pennsylvania State University

  • Anthony R Richardella

    • Pennsylvania State University

  • K. Andre Mkhoyan

    • University of Minnesota

  • Nitin Samarth

    • Pennsylvania State University