Magnetic multilayers consisting of repeated bilayers of cobalt and nickel or quadrilayers of cobalt, platinum, nickel and platinum were investigated using reflection and diffraction of X-rays. It was found that ultra-thin Co/Ni multilayers deposited with dual electron beam evaporation grow with poor interface quality, which is partly caused by high interdiffusion of Co and Ni, partly by cumulative interface roughness. The low interface quality destroyed the superlattice structure after a few bilayers in our samples. The quality of superlattice in Co/Pt/Ni/Pt multilayers was substantially better, which was mainly due to the lower mutual diffusion of platinum and cobalt, and platinum and nickel. For the Co/Pt/Ni/Pt multilayers, X-ray reflectivity measurements yielded information on thickness and interface roughness of individual layers. These characteristics were compared with thickness and interface roughness obtained from X-ray diffraction. X-Ray diffraction was also applied to get information on atomic ordering in individual layers (mean interplanar spacing and atomic disorder).