Evidence for a Josephson tunnel current in all {ital in situ} c-YBa{sub 2}Cu{sub 3}O{sub 7}/Pb junctions
- C.S.N.S.M., CNRS-IN2P3 Batiment 108 Universite Paris-Sud, 91405 Orsay (France)
All {ital in situ} YBu{sub 2}Cu{sub 3}O{sub 7}/Pb and YBa{sub 2}Cu{sub 3}O{sub 7}/Ag/Pb planar tunnel junctions have been successfully made on c-axis-oriented YBa{sub 2}Cu{sub 3}O{sub 7} thin films grown by a coevaporation technique, which show very-low-leakage I-V characteristics. The junctions are hysteretic and display a Josephson current I{sub c} below 7.2 K (lead T{sub c}). The only modification introduced by Ag is a substantial lowering of the normal-state resistance R{sub n}, but the I{sub c}R{sub n} product remains roughly constant. The magnetic-field modulation of I{sub c} shows that the current distribution is rather homogeneous over the whole junction area (0.5 mm{sup 2}), and follows the expected behavior for a short junction on a thin film (thickness {lt}{lambda}{sub ab}). The Josephson coupling between a conventional superconductor and the high-T{sub c} compound YBa{sub 2}Cu{sub 3}O{sub 7} along its c axis indicates that an s component is present in the superconducting order parameter of this material. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 450406
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 6 Vol. 55; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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