Field-Induced Magnetic Monopole Plasma in Artificial Spin Ice

ORAL

Abstract

Artificial spin ices (ASIs) are interacting arrays of lithographically-defined nanomagnets in which novel frustrated magnetic phases can be intentionally designed. A key emergent description of fundamental excitations in ASIs is that of magnetic monopoles - mobile quasiparticles that carry an effective magnetic charge. Here we demonstrate that the archetypal square ASI lattice can host, in specific regions of its magnetic phase diagram, plasma-like regimes containing a high density of mobile magnetic monopoles. These regimes result from the magnetic field-tunable tension on the Dirac strings connecting mobile monopoles. By passively "listening" to spontaneous monopole noise under conditions of strict thermal equilibrium, we reveal their intrinsic dynamics and show that monopole kinetics are most diffusive (that is, minimally correlated) in the plasma regime. These results open the door to on-demand monopole regimes having continuously field-tunable densities and dynamic properties, thereby providing a new paradigm for probing the physics of effective magnetic charges in synthetic matter.

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Presenters

  • Mateusz Goryca

    • National High Magnetic Field Laboratory
    • Los Alamos National Laboratory

Authors

  • Mateusz Goryca

    • National High Magnetic Field Laboratory
    • Los Alamos National Laboratory

  • Xiaoyu Zhang

    • Department of Applied Physics, Yale University
    • Yale University

  • Jing Li

    • National High Magnetic Field Laboratory
    • Los Alamos National Laboratory

  • Andrew L Balk

    • Los Alamos National Laboratory

  • Justin Watts

    • School of Physics and Astronomy, University of Minnesota
    • University of Minnesota

  • Chris Leighton

    • University of Minnesota
    • Department of Chemical Engineering and Materials Science, University of Minnesota

  • Cristiano Nisoli

    • Theoretical Division, Los Alamos National Laboratory
    • Los Alamos National Lab
    • Los Alamos Natl Lab
    • Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory
    • Los Alamos National Laboratory

  • Peter Schiffer

    • Yale University
    • Department of Applied Physics, Yale University
    • Department of Applied Physics and Department of Physics, Yale University

  • Scott Crooker

    • National High Magnetic Field Laboratory, Los Alamos National Laboratory
    • National High Magnetic Field Laboratory
    • Los Alamos National Laboratory