Topological Kinetics in a Vertex-Frustrated Artificial Spin Ice Nanomagnet Array

We have experimentally investigated and imaged how the topology of a frustrated artificial spin ice nanomagnet array can affect and constrain its kinetics. Studying vertex-frustrated Santa Fe artificial spin ice, in which magnetic excitations are correlated in thermally active one-dimensional emergent strings, we imaged the thermally-driven motion of these emergent string excitations in real time. At high temperatures, the string kinetics include topologically complex changes, which are highly constrained at lower temperatures. This system provides an unusually accessible venue in which to study the effects of topology on ergodicity through direct measurement of the thermal kinetics.