The Proximity and Josephson Effects in Niobium Nitride–Aluminum Bilayers

Highly disordered thin films of niobium nitride and the specific features of the proximity effect in NbN (S)–aluminum (N) bilayers with a large resistivity ratio, ρ NbN /ρ Al 1, are studied. It is shown that magnetic screening and the critical current I c of such SN structures significantly increase compared to the S layer. The observed effect is associated with the induced superconductivity in the N layer due to the proximity effect. The Josephson effect is demonstrated in NbN/Al–NbN–NbN/Al variable thickness bridges made of such SN bilayers.