Characterization of Superconductors by Surface Wave Techniques.
Abstract
The objective of this research project was to initiate a program to characterize superconductors by means of ultrasonic surface waves. Initially thin films Beta-tungsten and rocksalt superconductors were investigated. Measurements on Nb3Ge determined the superconducting fraction of the film as a function of temperature and the electron mean free path. Measurements on Nb3Sn determined the temperature dependent of superconducting energy gap and the upper critical field of the film. Measurements on several NbN films appear to indicate that there is a new interaction mechanism between the surface wave and the superconducting excitations in this rocksalt structure compound. The initial phase of the study on the effect of nickel films on the propagation of ultrasonic surface waves has been completed. Ultrasonic measurements have been performed on a polycrystalline sample of the ternary reentrant superconductor ErRh4B4 as a function of temperature where it is superconducting. Evidence is obtained for characterizing this superconductor as type II/I and for the fact that the transverse staggered susceptibility is screened by superconducting currents in the mixed state. Ultrasonic measurements have been performed in the superconducting and mixed states of bulk superconductors. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 28, 1980
- Accession Number
- ADA092387
Entities
People
- Moises Levy
Organizations
- University of Wisconsin–Milwaukee