Superconducting micronets: A state-variable approach

Journal Article · Wed May 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.10151· OSTI ID:5461666

Fink, H J; Haley, S B ^[1]

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1. Department of Electrical Engineering and Computer Science, University of California, Davis, Davis, California 95616 (USA)

A state-variable formulation of the nonlinear Ginzburg-Landau equations for superconducting micronets is introduced. The state variables are the Cooper-pair density {ital N}, kinetic energy {ital E}, and the imaginary part {ital I} of the Cooper-pair momentum density {ital scrP}. Purely algebraic relations among the state variables are derived, and several fundamental properties of micronets are proven. The current density {ital J}=Re{ital scrP} is given by {ital J}{sup 2}={ital NE}{minus}{ital I}{sup 2}, where {ital I}=Im{ital scrP}. For the limit {ital N}{much lt}1, a quasilinear theory yields the superfluid velocity {ital Q} as the only relevant transport parameter at the phase-transition boundary. Applying the full nonlinear theory, the maximum supercurrent that can be injected into a microladder is calculated as a function of normalized nodal spacing {ital scrL}/{xi}({ital T}) and magnetic flux {phi} for low magnetic fields, where {xi}({ital T}) is the temperature-dependent coherence length. The critical current {ital J}{sub {ital c}} approaches zero at a new temperature-critical flux boundary, {phi}{sub {ital c}1}({ital T}), which is first order and distinct from the second-order phase-transition boundary, {phi}{sub {ital c}2}({ital T}).

• OSTI ID: 5461666
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:13; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

656100* -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRITICAL CURRENT
CURRENTS
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
GINZBURG-LANDAU THEORY
MAGNETIC FLUX
NONLINEAR PROBLEMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SUPERCONDUCTORS