Domain dynamics of a ferromagnetic CoFe/Ni multilayer in response to ultrafast optical pumping

ORAL

Abstract

We studied a response of nanoscale magnetic domains in a 50 nm thick [Co90Fe10/Ni] multilayer to a femtosecond laser pulse by use of time-resolved soft X-ray resonant magnetic scattering (RMS) at the Linear Coherent Light Source. By collecting X-ray diffraction at high scattering angles, we observe the 1st, 3rd and 5th order RMS intensity peaks and thus capture the dynamics of fine magnetic features. We observe a rapid shift in the position of all diffraction orders towards smaller scattering angles and a simultaneous reduction of their magnitude. Surprisingly, higher orders start to decline relative to the 1st order only after a few picoseconds. With our data, we develop a method to extract real-space domain dynamics. We find that the dynamics across the domains are non-uniform, with smaller domains demagnetizing stronger than their larger neighbors. The domain walls remain relatively unchanged and start to broaden only after a few picoseconds. Using our models we attribute this behavior to a combined effect of non-uniform spin transport and a gradient in the absorption of the laser pump throughout the sample.

*The authors acknowledge support from the Department of Energy (DOE) Office of Basic Energy Sciences X-Ray Scattering Program Awards No. DE-SC0002002 and DE-SC0018237

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Presenters

  • Dmitriy Zusin

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

Authors

  • Dmitriy Zusin

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

  • Ezio Iacocca

    • University of Colorado, Boulder

  • Löic Le Guyader

    • European XFEL
    • European X-Ray Free-Electron Laser Facility GmbH

  • Adam Blonsky

    • University of Colorado, Boulder / JILA

  • Alex Reid

    • SLAC National Accelerator Laboratory
    • SLAC
    • SLAC National Accelerator Laboratory, Menlo Park, CA, United States

  • William F Schlotter

    • SLAC National Accelerator Laboratory
    • SLAC
    • SLAC National Accelerator Laboratory, Menlo Park, CA, United States

  • TianMin Liu

    • Physics, Stanford University
    • Stanford University / LCLS, Menlo Park, CA, United States

  • Daniel J Higley

    • Physics, Stanford University
    • Stanford University / LCLS, Menlo Park, CA, United States

  • 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

  • Sheena Patel

    • Physics, University of California, San Diego
    • University of California San Diego

  • Anatoly Shabalin

    • University of California, San Diego
    • Physics, University of California, San Diego
    • University of California San Diego

  • Nelson Hua

    • University of California, San Diego
    • Physics, University of California, San Diego
    • University of California San Diego

  • Stjepan Hrkac

    • University of California, San Diego
    • Physics, University of California, San Diego
    • University of California San Diego

  • 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

  • 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

  • Mark A Hoefer

    • University of Colorado, Boulder

  • 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

  • Eric Fullerton

    • Electrical and Computer Engineering, University of California San Diego
    • University of California, San Diego
    • Center for Memory and Recording Research, Univesrity of California, San Diego
    • Electrical and Computer Engineering, University of California, San Diego
    • University of California San Diego

  • Hermann Durr

    • Uppsala University, Sweden

  • 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