Scale transformation of magnetic "bubble" arrays: coupling of topological disorder and polydispersity.

The evolution of disorder in response to period adaptation in a hexagonal magnetic bubble array is shown to arise from the proliferation of dislocations and to proceed by means of intermediate states of steadily decreasing hexatic order to an amorphous final state. Remarkably, each dislocation core imposes a size adjustment on bubbles decorating its constituent pair of five- and sevenfold coordinated sites. Topological disorder thus induces intrinsic polydispersity and converts the initially unimodal size distribution into a trimodal one. This intimate interplay between geometry and topology provides an explicit mechanism by which structural disorder arises as a result of frustration.