A, Co/Cu multilayer system, with double layer thickness of about 60 nm was Auger electron spectroscopy depth profiled applying I keV Ar+ bombardment, varying the angle of incidence in the range of 78degrees-86degrees. It was found that (a) the relative sputter rate changes with the angle of incidence; (b) the interface broadening of the Co/Cu transition is larger than that of the Cu/Co transition and depends on the depth; (c) the broadening of the Co/Cu transition increases with increasing relative sputter rate; and (d) the broadening of the Cu/Co transition does not depend on the relative sputter rate. These features will be explained as the consequences of the strong preferential sputtering of Cu (with respect to Co) in this angular range. Because of the preferential sputtering ion bombardment induced roughening and smoothening (which was directly observed by atomic force microscopy measurements) occurs on the Co/Cu and Cu/Co interface, respectively. D-TRIM simulation has been also performed which suggested that ion mixing also causes larger broadening on the Co/Cu than on the Cu/Co interface. (C) 2003 American Vacuum Society.