Ultrafast Study of Dynamic interfacial Exchange Coupling in Ferromagnet/Oxide/Semiconductor Heterostructures

ORAL

Abstract

Time-resolved Kerr/Faraday rotation (TRKR/TRFR) is employed to study GaAs spin dynamics in the regime of strong and dynamic exchange coupling to an adjacent MgO/Fe layer. This study reveals a dramatic, resonant suppression in the inhomogeneous spin lifetime (T2*) in the GaAs layer. Further investigation of the magnetization dynamics of the neighboring Fe layer, also using TRKR/TRFR, reveals not only the expected Kittel-dispersion but also additional lower frequency modes with very short lifetime (~65 ps) that are not easily observed with conventional ferromagnetic resonance (FMR) techniques. These results suggest the intriguing possibility of resonant dynamic spin transfer between the GaAs and Fe spin systems. We discuss the potential for this work to establish GaAs spin dynamics as an efficient detector of spin dissipation and transport in the regime of dynamically-driven spin injection in ferromagnet/semiconductor heterostructures.

*Center for Emergent Materials; U.S. Department of Energy

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Authors

  • Yu-Sheng Ou

    • The Ohio State University

  • Yi-Hsin Chiu

    • The Ohio State University

  • Nicholas Harmon

    • University of Iowa
    • The University of Iowa

  • Patrick Odenthal

    • University of California, Riverside

  • Matthew Sheffield

    • The Ohio State University

  • Michael Chilcote

    • The Ohio State University

  • Roland Kawakami

    • The Ohio State University

  • Michael E. Flatté

    • University of Iowa
    • The University of Iowa

  • Ezekiel Johnston-Halperin

    • Dept. of Physics, The Ohio State University
    • The Ohio State University