Rewritable artificial magnetic charge ice

From a bar to a charge, magnetically Artificial spin ices are arrays of nanoscale bar magnets that can mimic the behavior of naturally occurring “frustrated” magnetic materials. Usually the arrays take the form of a square lattice with the bar magnets perpendicular to its sides. Wang et al. “broke up” each bar into a positive and negative magnetic charge. Working backward from an array of these charges, they designed a structure that has bar magnets oriented not only perpendicularly to the sides of the square lattice but also diagonally. Compared to the traditional one, this structure was much more controllable by global and local magnetic fields. Science, this issue p. 962 Multiple long-range orders, as well as local manipulation, are demonstrated in an unconventional artificial spin ice structure. Artificial ices enable the study of geometrical frustration by design and through direct observation. However, it has proven difficult to achieve tailored long-range ordering of their diverse configurations, limiting both fundamental and applied research directions. We designed an artificial spin structure that produces a magnetic charge ice with tunable long-range ordering of eight different configurations. We also developed a technique to precisely manipulate the local magnetic charge states and demonstrate write-read-erase multifunctionality at room temperature. This globally reconfigurable and locally writable magnetic charge ice could provide a setting for designing magnetic monopole defects, tailoring magnonics, and controlling the properties of other two-dimensional materials.