Magnetization reversal in submicron ferromagnetic dots and antidots arrays

Arrays of submicron Co rectangular dots with the aspect ratio ranging from 1 to 4 and antidots with the aspect ratio 4 were prepared by a high resolution lithography technique. Magnetic force microscope observations and magnetization measurements show that the magnetic state of square Co dots are well controlled by the shape anisotropy, whereas the antidots exhibit peculiar stripe domains at the remanent state. The direction of the stripes are well determined by the previously applied field direction.