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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