Influence of Topological Charge Parity on Square Artificial Spin Ices with Edge Dislocations*

Frustration in correlated spin systems gives rise to interesting collective phenomena that are central to condensed matter research. One successful approach to studying frustration in spin systems is the fabrication of lattices of single domain nanomagnets, referred to as artificial spin ices (ASI). ASIs can be tuned geometrically to realize exotic systems that would be otherwise difficult to access experimentally. For example, topological defects can be difficult to isolate in naturally occurring crystalline systems, but they can be directly patterned into an ASI. One system and defect of interest is the square ASI with edge dislocations. The square ASI orders into an antiferromagnetic (AFM) ground state; however, Drisko et al. showed that a single edge dislocation introduces magnetic frustration. As a result, the system relaxes into one of many nearly degenerate states with a domain wall extending from the defect to the system boundary. We previously found that defects with charge 2 relieve frustration and yield a single domain AFM ground state and recently observed defects of charge 3 reintroduce frustration. Here we present numerical simulations that reveal the strong influence of topological charge parity on magnetic phase transitions and dynamics of square ASI.