Unidirectional Spin Hall Magnetoresistance in Antiferromagnetic Heterostructures

ORAL · Invited

Abstract

Unidirectional spin Hall magnetoresistance (USMR) has been widely reported in heavy metal/ ferromagnet bilayer systems. We observe the USMR in Pt/α-Fe2O3 bilayers where the α-Fe2O3 is an antiferromagnetic (AFM) insulator. Systematic field and temperature-dependent measurements confirm the magnonic origin of the USMR. The appearance of AFM-USMR is driven by the imbalance of creation and annihilation of AFM magnons by spin-orbit torque due to the thermal random field. However, unlike its ferromagnetic counterpart, theoretical modeling reveals that the USMR in Pt/α-Fe2O3 is determined by the antiferromagnetic magnon number with a non-monotonic field dependence. Our findings extend the generality of the USMR which paves the way for the highly sensitive detection of AFM spin state.

* The authors from University of California, Los Angeles acknowledge the support from the National Science Foundation (NSF) Grants No. 1411085, No. 1810163, No. 1935362, No. 1909416, No. 1810163, and No. 1611570; the Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems (TANMS); the Intel Corporation under Contract No. 52318957; and the Army Research Office Multidisciplinary University Research Initiative (MURI) under Grants No. W911NF16-1-0472 and No. W911NF-19-S-0008. This work at the University of California, Riverside is supported by the Air Force Office of Scientific Research under Grant No. FA9550- 19-1-0307. The work at Ohio State University was supported by the Department of Energy (DOE), Office of Science, Basic Energy Sciences, under Grant No. DESC0001304 (film growth and structural characterization).

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Presenters

  • Yang Cheng

    University of California, Los Angeles

Authors

  • Yang Cheng

    University of California, Los Angeles