Double stacked superconducting junctions for investigating the proximity effect in Nb/Al bilayers

Experimental investigations on the proximity effect in Nb/Al bilayers by using
Nb/AlxOy/Nb/Al/AlxOy/Nb structures with different Al thickness are reported. Three-terminal
stacked devices were fabricated by using a new process based on a whole-wafer deposition
of the multilayer without any vacuum breaking in order to ensure a high control of the
interfaces. The quasiparticle density of states at both sides of the bilayer and the effective
interface coupling parameters were obtained by a deconvolution of the I-V data. They ...