Coherent ac spin current transmission across an antiferromagnetic CoO insulator

ORAL

Abstract

The recent discovery of spin-current transmission through antiferromagnetic insulating materials opens up vast opportunities for fundamental physics and spintronics applications. The question currently surrounding this topic is: whether and how could THz antiferromagnetic magnons mediate a GHz spin current? This mis-match of frequencies becomes particularly critical for the case of coherent ac spin-current, raising the fundamental question of whether a GHz ac spin-current can ever keep its coherence inside an antiferromagnetic insulator and so drive the spin precession of another ferromagnet layer coherently? Utilizing element- and time-resolved x-ray pump-probe measurements on Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructures, here we demonstrate that a coherent GHz ac spin current pumped by the Py ferromagnetic resonance can transmit coherently across an antiferromagnetic CoO insulating layer to drive a coherent spin precession of the Fe75Co25 layer. Further measurement results favor thermal magnons rather than evanescent spin waves as the mediator of the coherent ac spin current in CoO.

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Presenters

  • Qian Li

    • University of California, Berkeley

Authors

  • Qian Li

    • University of California, Berkeley

  • Mengmeng Yang

    • University of California, Berkeley
    • Department of Physics, UC Berkeley

  • Christoph Klewe

    • Lawrence Berkeley National Lab
    • Advanced Light Source

  • Padraic Shafer

    • Lawrence Berkeley National Lab
    • Advanced Light Source, LBNL
    • Advanced Light Source
    • Lawrence Berkeley National Laboratory, Advanced Light Source
    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory

  • Alpha T. N'Diaye

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Adv Light Source LBL

  • Dazhi Hou

    • Tohoku University
    • Hefei National Laboratory for Physical Sciences at the Microscale (HFNL), University of Science and Technology, China

  • Tianye Wang

    • University of California, Berkeley

  • Nan Gao

    • University of California, Berkeley

  • Eiji Saitoh

    • Tohoku University
    • Department of Applied Physics, The University of Tokyo
    • University of Tokyo
    • Univ of Tokyo

  • Chanyong Hwang

    • Korea Research Institute of Standards and Science

  • Robert J Hicken

    • University of Exeter

  • Jia Li

    • Peking Univerisity

  • Elke Arenholz

    • Lawrence Berkeley National Lab
    • Advanced Light Source, LBNL
    • Adv Light Source LBL

  • Zi Q. Qiu

    • University of California, Berkeley
    • Department of Physics, UC Berkeley