Fractional Shapiro steps in ladder Josephson arrays
- Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
We study the response of Josephson ladder arrays (1{times}{ital N} plaquettes) to a combined ac and dc current. For {ital N}{ge}1, the arrays are predicted to exhibit Shapiro steps at voltages {l angle}{ital V}{r angle}={ital nN}{h bar}{omega}/(2{ital e}) for {ital n}=1/2,1,3/2, . . ., over a broad range of fields {ital f}={Phi}/{Phi}{sub 0} ({Phi}=flux per plaquette, {Phi}{sub 0}={ital hc}/2{ital e}). The calculated half-steps persist even in single-plaquette arrays'' at all fields {ital f}{ne}0, and, when the critical currents parallel to the applied current are sufficiently unequal, even at {ital f}=0. Measurements of the step widths {Delta}{ital I}{sub 1/2}({ital f}) and {Delta}{ital I}{sub 1}({ital f}) for 1{times}600 ladder arrays of Nb-Au-Nb junctions are in good agreement with the calculations.
- DOE Contract Number:
- FG02-90ER45427
- OSTI ID:
- 7111270
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:21; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360107* -- Metals & Alloys-- Superconducting Properties-- (1992-)
665411 -- Basic Superconductivity Studies-- (1992-)
665412 -- Superconducting Devices-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
ELEMENTS
FLUCTUATIONS
GOLD
GRAIN BOUNDARIES
JOSEPHSON JUNCTIONS
JUNCTIONS
LATTICE PARAMETERS
METALS
MICROSTRUCTURE
NIOBIUM
PROXIMITY EFFECT
SUPERCONDUCTING JUNCTIONS
TRANSITION ELEMENTS
VARIATIONS