Double-period [(Pt 1.7 nm/Fe 0.9 nm)(5)Fe(tFeA(2))](8) and [(Pt 1.8 nm/Fe 0.6 nM)(5)Fe(t(Fe2))](8) multilayers with different thickness t(Fe2) (between 0.23 and 4.32 nm) of the additional Fe layers, prepared by combinatorial sputter deposition, show differences in the mosaic spread and the vertical interfacial roughness when deposited on native or thermally oxidised Si wafers. Simulations of the wide-angle X-ray scattering intensities revealed the presence of interdiffusion in the (Pt/Fe)(5) bilayers and systematic variations of the grain sizes, perpendicular to the film surface, as well as the rms variations of the two superlattice periods with the total film thickness. A comparison of omega-rocking scans shows an increase of the correlated vertical roughness of the (Pt/Fe)5 multilayers with the total multilayer thickness. (c) 2006 Elsevier B.V. All rights reserved.