Topological frustration of artificial spin ice

TL;DR

This study introduces topological defects into artificial spin ice, revealing how dislocations induce extended frustration and domain walls, highlighting the significant impact of topology on magnetic frustration.

Contribution

It demonstrates how lattice dislocations create extended frustration in artificial spin ice, a novel insight into the role of topological defects in frustrated magnetic systems.

Findings

Dislocations produce domain walls with indeterminate configurations.

Frustration persists away from dislocations due to lattice topology.

Topological defects significantly influence magnetic frustration.

Abstract

Frustrated systems, typically characterized by competing interactions that cannot all be simultaneously satisfied, display rich behaviours not found elsewhere in nature. Artificial spin ice takes a materials-by-design approach to studying frustration, where lithographically patterned bar magnets mimic the frustrated interactions in real materials but are also amenable to direct characterization. Here, we introduce controlled topological defects into square artificial spin ice lattices in the form of lattice edge dislocations and directly observe the resulting spin configurations. We find the presence of a topological defect produces extended frustration within the system caused by a domain wall with indeterminate configuration. Away from the dislocation, the magnets are locally unfrustrated, but frustration of the lattice persists due to its topology. Our results demonstrate the non-trivial nature of topological defects in a new context, with implications for many real systems in which a typical density of dislocations could fully frustrate a canonically unfrustrated system.