Observations of the a.c. Josephson Effect in High- T c YBaCuO Point Contacts
- 1 August 1987
- journal article
- Published by IOP Publishing in Europhysics Letters
- Vol. 4 (3) , 357-363
- https://doi.org/10.1209/0295-5075/4/3/017
Abstract
We have observed r.f.-induced Josephson steps using 70 GHz radiation in point contacts comprised of samples of YBaCuO which had a Tc ~ 80 K. Low junction resistances (~ 100 Ω) produced d.c. supercurrents of (2÷5) μA. At a temperature of 4.2 K, r.f.-induced steps up to n = 5 in YBaCuO/YBaCuO point contacts and up to n = 8 in NbZr/YBaCuO point contacts corresponding to a Josephson frequency of 350 GHz and 560 GHz, respectively, were observed. Step separation and step height dependence on the r.f. level were in agreement with ordinary Josephson tunnelling behaviour. These results imply singlet-state pairing of the electrons in the new superconducting materials.Keywords
This publication has 8 references indexed in Scilit:
- Energy gap in the high- superconductorPhysical Review B, 1987
- Superconductivity at 93 K in a new mixed-phase Y-Ba-Cu-O compound system at ambient pressurePhysical Review Letters, 1987
- Possible highT c superconductivity in the Ba?La?Cu?O systemZeitschrift für Physik B Condensed Matter, 1986
- Chaotic states of rf-biased Josephson junctionsJournal of Applied Physics, 1981
- Josephson effect between superconductors in possibly different spin-pairing statesPhysical Review B, 1977
- Effect of thermal noise on current-voltage characteristics of Josephson junctionsPhysical Review B, 1974
- Superconductivity in ultrathin films II. Structure in tunneling curvesZeitschrift für Physik B Condensed Matter, 1974
- Millimeter-Wave Mixing with Josephson JunctionsPhysical Review B, 1968