Domain formation in arrays of square holes in a Fe film

Domain formation during magnetization reversal in arrays of square holes in Fe films is investigated using the diffracted magneto-optic kerr effect (DMOKE). The shape of the domains can, in some cases, be extracted from hysteresis loops measured at various diffraction orders. We find that the shape of the domains depends strongly on: the direction of the applied field relative to the holes, the size of the square holes, and also the small intrinsic anisotropy of the unpatterned film. DMOKE results are compared with those obtained with magnetic force microscopy. In the saturated state Brillouin spectroscopy shows that square holes induce a fourfold anisotropy in the film.