Stable antiparallel domains in 3D corrugated magnetic thin films.

Magnetic nanostructured materials are of great interest in fields such as non-conventional computing or magnetic field sensing due to the possibilities that 3D magnetic textures embedded on metamaterials offer. We present a novel study on the magnetization and magneto-optical properties of a ferromagnetic (permalloy), continuous thin film that is highly corrugated by its deposition on the surface of a triangular silicon nanograting with a low periodicity (250 nm) and a quite large amplitude (180 nm), which leads to the formation of an unusual magnetic texture. This grating profile activates several optical phenomena and thus hinders magnetic characterization, which usually requires the analysis of the magneto-optical Kerr effect (MOKE); however, in this paper we unveil the magnetization and disclose magnetic features sized smaller than the light wavelength.