Nonlinear viscous motion of vortices in Josephson contacts
- Applied Superconductivity Center, University of Wisconsin, Madison, Wisconsin 53706 (United States)
Nonlinear dynamics of vortices in current-carrying long Josephson contacts is considered for the cases of weak ([lambda][sub [ital J]][much gt][lambda]) and strong ([lambda][sub [ital J]][much lt][lambda]) couplings, where [lambda][sub [ital J]] and [lambda] are the Josephson and London penetration depths, respectively. The first case concerns the Josephson vortices described by the sine-Gordon equation, whereas the case [lambda][sub [ital J]][much lt][lambda] corresponds to Abrikosov-like vortices with highly anisotropic Josephson cores which are described by an integral equation for the phase difference [ital cphi] within the framework of a nonlocal Josephson electrodynamics. At [lambda][sub [ital J]][much lt][lambda], an exact solution for the moving vortex in the overdamped regime is obtained, the fluxon velocity [ital v]([ital j]) and the voltage-current characteristic [ital V]([ital j]) are calculated. It is shown that the lack of the Lorentz invariance of the integral equation for [ital cphi] in the nonlocal regime leads to specific features of the vortex dynamics as compared to the Josephson vortices. The results obtained are employed for the description of nonlinear viscous motion of magnetic flux along planar crystalline defects in superconductors. It is shown that any percolating network of planar defects can considerably reduce the critical current, change the field dependence of the flux-flow resistivity, and result in a nonlinear [ital V]([ital j]) in the flux-flow regime.
- OSTI ID:
- 5921014
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 48:17; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
JOSEPHSON JUNCTIONS
VORTICES
CRYSTAL DEFECTS
DYNAMICS
MAGNETIC FLUX
NONLINEAR PROBLEMS
SINE-GORDON EQUATION
VISCOSITY
CRYSTAL STRUCTURE
EQUATIONS
FIELD EQUATIONS
JUNCTIONS
MECHANICS
SUPERCONDUCTING JUNCTIONS
665411* - Basic Superconductivity Studies- (1992-)