Spin-orbit torque generated by amorphous Fe<sub>x</sub>Si<sub>1-x</sub>

ORAL

Abstract

Despite the tremendous amount of work that has gone into spin-orbit torque and spin current generation in heavy metals, questions on the origin of the underlying physics still remain, often stemming from the challenge in differentiating between spin currents that are generated from the bandstructure of the heavy metal, and other sources, such as inversion symmetry breaking at the interface and or scattering. Here we report observation of spin-orbit torque under room temperature in fully amorphous non-magnetic Fe(x)Si(1-x)/cobalt bilayer via spin-torque ferromagnetic resonance and harmonic Hall measurements. Both techniques provide a consistent spin Hall angle of about 3%. According to the conventional theory of the spin Hall effect, a spin current in an amorphous material is not expected to have any contribution from the bandstructure. Despite this fact, our observation of a reasonably strong spin-orbit torque paves a new avenue for understanding the underlying physics of spin-orbit interaction.

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Presenters

  • Cheng-Hsiang Hsu

    • Electrical Engineering and Computer Science, University of California, Berkeley
    • EECS, University of California, Berkeley

Authors

  • Cheng-Hsiang Hsu

    • Electrical Engineering and Computer Science, University of California, Berkeley
    • EECS, University of California, Berkeley

  • Julie E Karel

    • Materials Science and Engineering, Monash University

  • Niklas Roschewsky

    • Physics, University of California, Berkeley
    • EECS, University of California, Berkeley

  • Dinah Simone Bouma

    • Physics, University of California, Berkeley
    • University of California, Berkeley, and Lawrence Berkeley National Laboratory
    • University of California Berkeley
    • University of California, Berkeley and Lawrence Berkeley National Laboratory

  • Scott Bennett

    • Materials Science and Engineering, Monash University

  • Alexander Nguyen

    • Materials Science and Engineering, Monash University

  • Suraj S Cheema

    • Materials Science and Engineering, University of California, Berkeley

  • Shehrin Sayed

    • Electrical Engineering and Computer Science, University of California, Berkeley
    • EECS, University of California, Berkeley
    • University of California, Berkeley

  • Frances Hellman

    • Physics, University of California, Berkeley
    • University of California, Berkeley
    • University of California, Berkeley, and Lawrence Berkeley National Laboratory
    • University of California Berkeley
    • University of California, Berkeley and Lawrence Berkeley National Laboratory

  • Sayeef Salahuddin

    • Electrical Engineering and Computer Science, University of California, Berkeley
    • EECS, University of California, Berkeley
    • University of California, Berkeley