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.

–

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