Fundamental Fluxoid-Defect Interactions in Irradiated Superconductors.
Abstract
Flux pinning experiments in irradiated superconductors which make it possible to independently vary the defect density rho and elementary interaction force f(p) between the defect and the fluxoid lattice are reviewed. A new measure of flux pinning, Q, the volume pinning force per defect, is introduced and is shown to be independent of rho for rho < 10 to the 22nd power/cu.m. In Nb at B = .5 Bc sub 2 and 4.2K, Q = 5x10 to the -18th power N for Frenkel defects, 3x10 to the -16th power N for cascades, 2x10 to the -15th power N for 100A dislocation loops and 3x10 to the -14th power N for 100A voids. The Q's for voids and loops increase strongly with void or loop diameter. Accurate estimates of f(p) for voids and dislocation loops can be made and plotted versus Q. The results for the two defects overlap forming a single master curve that can be used as an experimental solution to the summation problem. Reasons why current summation models do not reproduce the master curve are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1977
- Accession Number
- ADA044734
Entities
People
- Edward J. Kramer
Organizations
- Cornell University