Proximity effect in flux pinning
Journal Article
·
· J. Appl. Phys.; (United States)
The elementary interaction force f/sub p/ for a small normal conducting precipitate particle is usually estimated assuming that the entire condensation energy of the superconductor 1/2 ..mu../sub 0/H/sup 2//sub c/ is lost in the volume of the particle, i.e., that the particle is equivalent to a void. It is demonstrated that this assumption, which neglects the proximity effect, leads to a serious over estimate of f/sub p/, by as much as three orders of magnitude. The ratio of f/sub p/ of a normal precipitate to f/sub p/ of a void of the same volume is shown to be of the order (t/xi/sub 0/)/sup 2/, where t is the smallest dimension of the particle and xi/sub 0/ is the BCS coherence length. In addition, the ratio is temperature dependent, becoming smaller (larger correction) as T approaches T/sub c/. These predictions are compared with recent experimental measurements of pinning by voids and precipitates and are shown to rationalize some hitherto puzzling experimental discrepancies between pinning by the two types of defects. Application of these ideas to flux pinning by other defects, such as grain boundaries and dislocations, is also discussed.
- Research Organization:
- Department of Materials Science and Engineering and the Materials Science Center, Cornell University, Ithaca, New York
- OSTI ID:
- 5122583
- Journal Information:
- J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 51:9; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
656102* -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BCS THEORY
COHERENCE LENGTH
COMPARATIVE EVALUATIONS
CRITICAL CURRENT
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CURRENTS
DATA
DISLOCATIONS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
GRAIN BOUNDARIES
INFORMATION
LINE DEFECTS
MAGNETIC FLUX
MATHEMATICAL MODELS
MICROSTRUCTURE
PHYSICAL PROPERTIES
PROXIMITY EFFECT
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
VOIDS
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BCS THEORY
COHERENCE LENGTH
COMPARATIVE EVALUATIONS
CRITICAL CURRENT
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CURRENTS
DATA
DISLOCATIONS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
GRAIN BOUNDARIES
INFORMATION
LINE DEFECTS
MAGNETIC FLUX
MATHEMATICAL MODELS
MICROSTRUCTURE
PHYSICAL PROPERTIES
PROXIMITY EFFECT
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
VOIDS