Nanoscale SEMPA imaging of an artificial quasicrystal spin ice at remanence

ORAL

Abstract

Artificial spin ice has emerged in the past decade as a model metamaterial for studying frustrated magnetic ordering at length scales large enough to be experimentally probed in real space. Recently, complex designs have been engineered to explore exotic behavior in non-square lattices. However, direct measurements of the actual moment directions have not been very common, and interpretation from techniques such as magnetic force microscopy and magneto-optical Kerr effect magnetometry can be complicated by the more complex geometries. Here we demonstrate using SEMPA (scanning electron microscopy with polarization analysis) as a method to robustly measure the ordering direction of elements in a connected artificial quasicrystal. We discuss the applicability of SEMPA to this system, details of the imaging and potential artifacts, and conclusions that can be drawn from the nanoscale two dimensional maps of the moment direction.

*This work is partially funded by DoE grant \#DE-FG02-97ER45653. ALB acknowledges support of this research under the Cooperative Research Agreement between the University of Maryland and NIST.

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Authors

  • Andrew Balk

    • Center for Nanoscale Science and Technology, NIST
    • Center for Nanoscale Science and Technology, National Institute of Standards and Technology
    • Center for Nanoscale Science and Technology, National Institute of Standards and Technology. Maryland Nanocenter, University of Maryland

  • Vinayak Bhat

    • University of Kentucky, Department of Physics and Astronomy

  • 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

  • John Unguris

    • Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899
    • Center for Nanoscale Science and Technology, NIST
    • Center for Nanoscale Science and Technology, National Institute of Standards and Technology
    • Center for Nanoscale Science and Technology, National Institute of Standards and Technology.