Artificial Dense Lattices of Magnetic Skyrmions.

Multilayer Co/Pt films with perpendicular magnetic anisotropy are irradiated by focused a He ion beam to locally reduce the anisotropy value. The irradiated spots with the diameters of 100 and 200 nm are arranged in square lattices with the periods of 200 and 300 nm. The formation of nonuniform magnetic states within the spots was observed by magnetic force microscopy methods.