CRITICAL CURRENT ENHANCEMENT IN SUPERCONDUCTING LEAD SAMPLES OF VARYING CROSS SECTION.
Abstract
It is found that the superconducting critical currents of lead samples of a certain shape are frequently far below the values one would expect from the application of Silsbee's rule ((H sub c)(G) = (I sub c) (A)/5r(cm)). Values as low as 20%-25% of those expected are typical. By various mechanical and chemical treatments of the surface and through use of certain solders, these degraded critical currents can be greatly restored, sometimes even to their full expected value. The trapping of magnetic flux in a specimen is also capable of enhancing its resistance-free current capacity either partially or fully; the degree of enhancement depending in samples that trap appreciable amounts of flux, it is shown that its maintenance requires only negligible amounts. Infrequently, samples are encountered in which enhancement may also be attained merely by exposure to sufficiently high transport currents. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1970
- Accession Number
- AD0710957
Entities
People
- H. A. Leupold
- J. J. Winter
- J. T. Breslin
Organizations
- United States Army Communications-Electronics Command