Abstract:
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, ρNbN/ρAl≫1, are studied. It is shown that magnetic screening and the critical current Ic 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.
This work was supported by the Russian Science Foundation (grant no. 15-12-10020: Investigation of the Josephson effect in NbN and Al bilayers) and by the Program of the Basic Research of the Presidium of the Russian Academy of Sciences no. 12 “Fundamental problems of high-temperature superconductivity”.
Citation:
M. Yu. Levichev, A. I. Elkina, N. N. Bukharov, Yu. V. Petrov, A. Yu. Aladyshkin, D. Yu. Vodolazov, A. M. Klushin, “The proximity and Josephson effects in niobium nitride–aluminum bilayers”, Fizika Tverdogo Tela, 61:9 (2019), 1594–1598; Phys. Solid State, 61:9 (2019), 1544–1548