Magnetic order and dynamics in Ammann-Beenker artificial magnetic quasicrystals

ORAL

Abstract

Artificial spin lattices (ASLs) consist of arrays of nanoscale magnets whose properties can be tuned by geometry and composition. Periodic ASLs, or artificial spin ices (ASIs), have been extensively studied as model systems for magnetic frustration (1, 2). ASIs are also emerging as platforms for unconventional computing (e.g., reservoir and neuromorphic) (3, 4). In contrast, understanding of aperiodic ASLs, artificial magnetic quasicrystals (AMQs), is limited. AMQs possess the aperiodicity of natural quasicrystals and can also exhibit complex magnetic order, frustration, and ground-state degeneracy. Here, we focus on the Ammann-Beenker AMQ (AB-AMQ), which is tiled using rhombi and squares (5). Thermally active AMQs were fabricated using permalloy (Ni0.8Fe0.2). Using photoemission electron microscopy (PEEM) imaging with x-ray magnetic circular dichroism (XMCD) as well as resonant x-ray scattering, we study the ground state ordering of the AB-AMQ and experimentally confirm the existence of degenerate ground states. Additionally, Monte Carlo simulations predict magnetic phase transitions in the AB-AMQ system. These dynamics were studied using temperature-dependent PEEM-XMCD and x-ray photon correlation spectroscopy.

1. Appl. Phys. Lett. 118, 110501 (2021).

2. Nat. Rev. Phys. 2, 13 (2020).

3. Nat. Nanotechnol. 17, 460 (2022).

4. Appl. Phys. Express 14, 033001 (2021).

5. J. Appl. Phys. 115, 17C502 (2014).

*This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC-0024346. This research used resources of the Advanced Light Source, a U.S. DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

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Presenters

  • Margaret R McCarter

    • University of California, Berkeley
    • Lawrence Berkeley National Laboratory

Authors

  • Margaret R McCarter

    • University of California, Berkeley
    • Lawrence Berkeley National Laboratory

  • Aastha Vasdev

    • Argonne National Laboratory
    • University of Kentucky

  • Justin Scott Woods

    • Argonne National Laboratory

  • Ralu Divan

    • Argonne National Laboratory
    • Center for Nanoscale Materials, Argonne National Laboratory

  • David A Czaplewski

    • Argonne National Laboratory

  • Lance Eric De Long

    • University of Kentucky

  • Sophie A Morley

    • Lawrence Berkeley National Laboratory

  • Sujoy Roy

    • Lawrence Berkeley National Laboratory

  • Todd Hastings

    • University of Kentucky