GLANCING-INCIDENCE X-RAY CHARACTERIZATION OF NB PD MULTILAYERS/

The study of periodic metallic multilayers in which one of the two con stituent layers is a superconductor has attracted considerable interes t. The structural configuration and quality of the interfaces is of fu ndamental importance because it influences the phases of the supercond uctive wave function in the interface region and, hence, the coupling between the nearest superconductive layers. In this work we present a structural investigation of Nb/Pd multilayers by using high- and low-a ngle X-ray diffraction measurements. All the samples were grown on Si( 100) substrates by de-triode sputtering. We investigated two samples c onsisting of 10 stacks of nominally 18 nm Nb, 4 nm Pd and 18 nm Nb, 8 nm Pd, respectively. The high-angle analyses reveal that the Nb layer is oriented in the [110] direction and the Pd in the [111] direction. Off-specular reflectivity measurements show the presence of a (partial ly) correlated roughness across the interfaces. From specular reflecti vity it was found how the rms roughness increases from the substrate t o the surface.