Dynamics of artificial square spin ice during a non-equilibrium field ramp and quench

ORAL

Abstract

Recent advances in nanotechnology make it possible to create arrays of single-domain ferromagnetic nanoislands that can be fabricated to mimic a variety of Ising-like model systems. This has opened up new ways of studying frustrated systems, such as artificial square spin ice. One of the main advantages of studying these nanomagnet systems is that the Ising-like moments can be directly visualized; but a persistent drawback has been the inaccessibility of the ground state, due to the highly athermal nature of these systems. We present the magnetic autocorrelation function of artificial square spin ice, as measured by XPCS following a non-equilibrium field quench. Our large-scale Monte Carlo simulations agree qualitatively with the experimental relaxation measurements. Furthermore, our simulation results indicate that a simple field ramping demagnetization protocol can be a viable way of reaching a low-energy state.

–

Authors

  • Juan Carlos Andresen

    Department of Theoretical Physics, KTH Stockholm

  • Shrawan Mishra

    Advanced Light Source, Lawrence Berkeley National Laboratory

  • James Lee

    Lawrence Berkeley National Laboratory and University of Oregon, Eugene, Advanced Light Source, Lawrence Berkeley National Laboratory \& Deptartment of Physics, University of Oregon, Lawrence Berkeley National Laboratory

  • Xiaowen Shi

    Advanced Light Source, Lawrence Berkeley National Laboratory \& Deptartment of Physics, University of Oregon

  • Barry Farmer

    University of Kentucky, University of Kentucky, Department of Physics and Astronomy

  • L.E. DeLong

    University of Kentucky, University of Kentucky, Department of Physics and Astronomy, Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA

  • Patrik Henelius

    Department of Theoretical Physics, The Royal Institute of Technology, Sweden, Department of Theoretical Physics, KTH Stockholm

  • Steve Kevan

    Advanced Light Source, Lawrence Berkeley National Laboratory

  • Sujoy Roy

    Lawrence Berkeley National Laboratory, Advanced Light Source, Lawrence Berkeley National Laboratory