Magnetic order in an Einstein Artificial Spin ice

Artificial spin ices (ASI) serve as model magnetic systems and are being considered for unconventional computing. Quasicrystalline ASIs have drawn significant interest because they exhibit magnetic order and collective interactions despite their aperiodicity. However, until this year, there was no known aperiodic tiling that used a single tile, an ”einstein” (from ”one stone”). The recent discovery of an equilateral einstein by Smith et al. inspired us to propose the einstein ASI in which identical, single- domain, nanoscale magnetic islands are placed on the sides of the polygons. Monte Carlo simulations indicate that the einstein ASI exhibits a magnetically ordered ground state and nearly degenerate similar states due to magnetic frustration. In our studies, we synthesized nanoscale einstein ASI and confirmed these predictions by characterizing them with magnetic force microscopy (MFM) and X-ray magnetic circular dichroism photoemission electron microscopy (XMCD-PEEM).