Theory of finite-size effects and vortex penetration in small Josephson junctions
- Department of Physics, Purdue University, 1396 PHYS building, West Lafayette, Indiana 47907-1396 (United States)
We present a study of finite-size effects in a small Josephson junction. Explicit expressions for the total magnetic field have been found for the case of the Meissner state and for that of an ordered array of Abrikosov vortices penetrating the electrodes. We have determined how the behavior of the critical current [ital I][sub [ital c]] as a function of the strength of an external magnetic field depends on the ratio [ital L]/[lambda][sub [ital x]] of the width of the junction to the appropriate London penetration length. For small [ital L]/[lambda][sub [ital x]] in particular, significant deviations from the familiar Fraunhofer pattern are found in a number of situations. We find that, in general, for the same field strength, because of an interesting cancellation property of the Josephson phase gradient, vortex penetration tends to increase the critical current. Moreover, for suitable vortex configurations [ital I][sub [ital c]] is found to be determined by the magnetization and to actually increase with the field. The relevance of our results for junctions made out of high-temperature superconductors is discussed.
- DOE Contract Number:
- FG02-90ER45427
- OSTI ID:
- 6712549
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 51:2; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRITICAL CURRENT
CURRENTS
ELECTRIC CURRENTS
EQUATIONS
JOSEPHSON JUNCTIONS
JUNCTIONS
LONDON EQUATION
MAGNETIC FLUX
MAGNETIZATION
MEISSNER-OCHSENFELD EFFECT
PENETRATION DEPTH
SUPERCONDUCTING JUNCTIONS
VORTICES