Ultrafast transfer of magnetization on magnetic sublattices in half-metallic Co2MnGe heusler alloys

ORAL

Abstract

Heusler alloys are exciting materials for future applications because they display a wide range of tunable electronic and magnetic interactions such as metallicity, ferromagnetism, superconductivity, and giant magneto-resistance. However, laser-induced spin dynamics in heuslers were expected to be slower than in conventional metallic ferromagnets, due to the presence of a blocked spin channel. Here we directly observe ultrafast spin transfer from one magnetic sublattice to another in half-metallic heusler alloy Co2MnGe, that occurs on the timescale of the femtosecond laser excitation. Ultrafast high harmonic pulses make it possible to simultaneously record the element-specific magnetic dynamics of Co and Mn as the material undergoes demagnetization. The magnetization of Co is transiently enhanced by 10% within 60 fs, while that of Mn rapidly quenches. By comparing our data to density functional theory, we show that optical excitation can directly transfer spin from one magnetic sub-lattice to another, due to spin-polarized optical excitation pathways. The observed transient enhancement of ferromagnetic ordering demonstrates fast manipulation of spin by light, thus providing a path towards spintronics logic devices that can operate on femtosecond or even attosecond timescales.

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Presenters

  • Phoebe Tengdin

    Physics, University of Colorado, JILA, University of Colorado Boulder, University of Colorado, Boulder / JILA, JILA, University of Colorado, Boulder

Authors

  • Phoebe Tengdin

    Physics, University of Colorado, JILA, University of Colorado Boulder, University of Colorado, Boulder / JILA, JILA, University of Colorado, Boulder

  • Christian Gentry

    JILA, University of Colorado Boulder, University of Colorado, Boulder / JILA, JILA, University of Colorado, Boulder

  • Dmitriy Zusin

    Physics, University of Colorado, JILA, University of Colorado Boulder, University of Colorado, Boulder / JILA, JILA, University of Colorado, Boulder

  • Adam Z Blonsky

    JILA, University of Colorado Boulder, JILA, University of Colorado, Boulder

  • Justin Shaw

    Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA, National Institute of Standards and Technology Boulder, Quantum Electromagnetics Division, NIST, Boulder, CO, United States, National Institute of Standards and Technology, Boulder CO

  • Hans T. Nembach

    Quantum Electromagnetics Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA, National Institute of Standards and Technology Boulder, JILA, University of Colorado, Boulder, Quantum Electromagnetics Division, NIST, Boulder, CO, United States, National Institute of Standards and Technology, Boulder CO

  • Monika Arora

    National Institute of Standards and Technology, Boulder CO, National Institute of Standards and Technology Boulder

  • Thomas Silva

    National Institute of Standards and Technology Boulder, NIST, Quantum Electromagnetics Division, NIST, Boulder, CO, United States, National Institute of Standards and Technology, Boulder CO

  • Yaroslav Kvashnin

    Physics and Astronomy, Uppsala University, Uppsala University

  • Erna Delczeg

    Uppsala University

  • Olle Eriksson

    Uppsala University, Uppsala University and Örebro University, Physics and Astronomy, Uppsala University

  • Henry C Kapteyn

    JILA, University of Colorado, Boulder, JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder / JILA, University of Colorado, Boulder

  • Margaret Mary Murnane

    JILA, University of Colorado, Boulder, JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder / JILA, University of Colorado, Boulder