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NbN /SUB x/ - NbO /SUB y/ - PbIn /SUB z/ Josephson junctions with r. f. oxidised tunneling barriers

Journal Article · · IEEE Trans. Magn.; (United States)
The authors report the fabrication of high quality Josephson tunnel junctions made by the r.f. sputter-deposition method. The characteristics of these junctions were determined at 4.2/sup 0/K as a function of the following fabrication parameters: the substrate temperature, the sputtering power during base electrode deposition, and the r.f. oxidation time for the barrier. The authors have obtained critical current densities from 90 to 800 Amperes/cm/sup 2/ which depended exponentially on the barrier formation time, a gap energy of 3.3meV, and hysteretic current-voltage characteristics. Thermal cycling of a few junctions resulted in small changes in the currentvoltage curves. Auger Electron Spectroscopy and ESCA of the films show that x=1.02, z=0.25, and that the niobium oxide is a mixture of Nb/sub 2/O/sub 5/ and the lower oxides, NbO and NbO/sub 2/, that are present at the oxidebase electrode interface.
Research Organization:
Dept. of Electrical Engineering and Applied Physics, Case Western Reserve University, Cleveland, OH 44106
OSTI ID:
5626077
Journal Information:
IEEE Trans. Magn.; (United States), Journal Name: IEEE Trans. Magn.; (United States) Vol. 19:3; ISSN IEMGA
Country of Publication:
United States
Language:
English