Experimental study of the ultimate limit of flux pinning and critical currents
A flux pinning model, which predicts the maximum critical current density attainable in superconductors, is reviewed and some additional conclusions and considerations, particularly in regard to the model are explored. That such a maximum must exist comes from the realization that flux pinning is strongest in regions of weak superconductivity, but these regions cannot carry a large supercurrent. Since the same regions within the superconductor cannot be used for both pinning and supercurrent conduction, there must be an optimum mix, leading to a maximum J/sub c/. Measurements on films and multilayers of NbN have verified many details of the model including anisotropy effects and a strong reduction in J/sub c/ for defect spacings smaller than the flux core diameter. In an optimized multilayer the pinning force reached /approximately/22% of the theoretical maximum. The implications of these results on the maximum critical current density in the new high temperature superconductors are also discussed. 12 refs., 1 fig.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6571316
- Report Number(s):
- CONF-8806281-1; ON: DE89003620
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRITICAL CURRENT
CRITICAL TEMPERATURE
CURRENT DENSITY
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE