Precipitating Ordered Skyrmion Lattices from Helical Spaghetti

Magnetic skyrmions are a focus of intense research due to their application to ultra-low power data storage and logic technologies as well as their fundamental qualities as topological psudo-particles. In this work we use small angle neutron scattering (SANS) to demonstrate a method to precipitate ordered and oriented skyrmion lattices from an initial domain configuration consisting of mutli-q helices and randomly oriented skyrmion arrays. This approach uses a symmetry-breaking magnetic field sequence to define a preferred orientation of the skyrmion lattice. We demonstrate this approach on single-crystals of (Fe, Co)Si. Interestingly, the efficacy of this technique is independent of the orientation of the crystal, suggesting a similar approach could be applied to a randomly oriented powdered sample. Indeed, we are able to precipitate ordered and oriented skyrmion lattices in a powdered sample of Cu₂OSeO₃. Simulations (OOMMF) reveal the underlying mechanics responsible for the ordering and also suggest that the resultant orientation of the skyrmion lattices differentialtes Bloch and Néel skyrmions. This approach means that candidate skyrmion materials can be tested as powders using SANS, significantly improving accessability to skyrmion research.