Research on Severely Deformed Superconductors.
Abstract
Severely deformed superconducting Nb behaves anomalously in several respects, including mixed-state RF loss and the inductive and resistive transitions. To measure the RF surface impedance as a function of magnetic field and frequency, a quarter-wave coaxial resonator in helical configuration was designed, analyzed and constructed. The results indicate that, as a function of frequency, mixed state RF loss is described very well by a 'two-fluid' model without reference to loss mechanism other than that fluxon core excitations are involved. At present there is no explanation for structure sensitivity or the huge change in depinning frequency with cold work. Tunneling experiments were performed on single crystal and deformed Nb, and the data inverted by a numerical program to yield the electron-coupled spectrum (alpha squared) F and strong-coupling parameters lambda, mu(*) and < omega >.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 27, 1975
- Accession Number
- ADA013492
Entities
People
- Robert Marc Rose
Organizations
- Massachusetts Institute of Technology