Magnetic behavior of Co/Pt multilayers deposited on nanosphere array

Ordered polystyrene particles were deposited onto the silicon substrate by the self-assembly process and the colloidal surfaces worked as the curved substrate. We fabricated perpendicular multilayer film [Co/Pt]n with the controllable strength and direction of anisotropy axis based on the 2D curved substrate in the magnetron sputtering system. In contrast to the same multilayer film deposited on flat Si substrate, the squareness hysteresis loops remained almost unchanged between 0∘ and 45∘ for the curved film, which indicated a narrow distribution of the switch field. All the observations were attributed to the variation of the anisotropy axis across the top of the sphere.