Influence of steps on quantum well states in Cu/Co(100) multilayers

Interface roughness is known to have a large effect on oscillatory magnetic coupling and giant magnetoresistance in magnetic multilayers, but the origin of this effect is still uncertain. In order to obtain a quantitative measure we have used vicinal Cu/Co(100) interfaces with well-defined step spacing and have determined the amplitude of quantum oscillations in the density of states that are correlated with oscillatory magnetic coupling. For a step spacing of 10 Å the oscillation amplitude decreases by a factor of 1.8. This distance corresponds to the lateral extent of the quantized states in the film.