Screening in Josephson-junction ladders
- Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
Both critical current and Shapiro steps in Josephson ladders are found to show effects of vortex exclusion below a critical magnetic field. Vortices are excluded even though the flux itself is {ital not} screened out. When current is injected perpendicular to the ladder edges, the critical current is unchanged from its {ital f}=0 value up to a penetration field of {ital f}{sub {ital c}1{perpendicular}}{approx_equal}0.12 flux quanta per plaquette. Similarly, there are only integer Shapiro steps below a critical {ital c}1{perpendicular}{asterisk}, where vortices first penetrate. A narrower critical current plateau also appears to form near {ital f} =1/2. No such plateaus occur when current is injected in the parallel direction. We attribute the exclusion in the perpendicular geometry to screening currents which flow along the edges of the ladder. {copyright} {ital 1996 The American Physical Society.}
- Research Organization:
- Purdue Univ., West Lafayette, IN (United States)
- DOE Contract Number:
- FG02-90ER45427
- OSTI ID:
- 277318
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 53, Issue 2; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
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