We have used scanning electron microscopy with polarization analysis and photoemission electron microscopy to image the two-dimensional magnetization of permalloy films patterned into Penrose P2 tilings (P2T). The interplay of exchange interactions in asymmetrically coordinated vertices and short-range dipole interactions among connected film segments stabilize magnetically ordered, spatially distinct sublattices that coexist with frustrated sublattices at room temperature. Numerical simulations that include long-range dipole interactions between sublattices agree with images of as-grown P2T samples and predict a magnetically ordered ground state for a two-dimensional quasicrystal lattice of classical Ising spins.
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Research at University of Kentucky was supported by U.S. DoE Grant DE-FG02-97ER45653, U.S. NSF Grant DMR-1506979, the UK Center for Advanced Materials, the UK Center for Computational Sciences, and the UK Center for Nanoscale Science and Engineering. AB acknowledges support of this research under the Cooperative Research Agreement between the University of Maryland and National Institute of Standards and Technology Center for Nanoscale Science and Technology, Award 70NANB10H193, through the University of Maryland. Research at the Advanced Photon Source, a U.S. Department of Energy Office of Science User Facility operated by Argonne National Laboratory, was supported under Contract No. DE-AC02-06CH11357.
See Supplemental Material at http://link.aps.org/supplemental/10.1103/PhysRevB.93.134428 for additional information regarding sample film fabrication, SEMPA imaging procedures, P2T sublattice identification procedures, and a complete set of all SEMPA images obtained in this study.
Farmer, Barry; Bhat, Vinayak Shantaram; Teipel, Eric; Unguris, J.; Keavney, D. J.; Hastings, Jeffrey Todd; and De Long, Lance E., "Direct Imaging of Coexisting Ordered and Frustrated Sublattices in Artificial Ferromagnetic Quasicrystals" (2016). Physics and Astronomy Faculty Publications. 431.