Textured heterogeneity in square artificial spin ice

We report evidence of spontaneous formation of a heterogeneous network of superdomains in two-dimensional square artificial spin ice nanostructures in externally applied magnetic fields. Coherent resonant soft-x-ray scattering from such textures gives rise to unique internal structure in Bragg peaks. The magnetic heterogeneity is locally disordered but has a zigzag texture at longer length scales. Our result suggests that the macroscopic magnetic texture is derived from the microscopic structure of the Dirac strings.