Erratum: Surface superconductivity in niobium and niobium-tantalum alloys

Journal Article · Thu Aug 01 04:00:00 EDT 1974 · Physical Review, B: Solid State

DOI:https://doi.org/10.1103/PhysRevB.10.1135· OSTI ID:4335606

Hopkins, J. R.; Finnemore, D. K.

The critical field for surface superconductivity, H/sub c3/ and the upper bulk critical field, H/sub c2/, have been measured as a function of temperature and mean free path for Nb and Nb(Ta) alloys in an attempt to study the spatial variations of the superconducting interaction constant N(O)V near a vacuum-metal interface. At temperatures below T/T/sub c/ = 0.85, the pure-Nb sample shows H/sub c3//H/sub c2/ values well above 1.695, as predicted by Hu and Korenman for the limit of long electronic mean free path. As the mean free path decreases, there is a regular depression of H/sub c3//H/sub c2/ toward 1.695. At temperatures above T/T/sub c/, = 0.85, however, there are striking deviations from the theory which may arise because the interaction constant is slightly depressed at the surface. A model calculation by Hu shows that changes in N(0)V at the surface of 0.7% for pure Nb and 1.6% for Nb-1.0-at.% Ta can account for the experimental results.

• Research Organization: Ames Laboratory-USAEC and Department of Physics, Iowa State University of Science and Technology, Ames, Iowa 50010
• Sponsoring Organization: USDOE
• NSA Number: NSA-29-025442
• OSTI ID: 4335606
• Journal Information: Physical Review, B: Solid State, Journal Name: Physical Review, B: Solid State Journal Issue: 3 Vol. 10; ISSN 0556-2805; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

*NIOBIUM BASE ALLOYS-- SUPERCONDUCTIVITY
*NIOBIUM-- SUPERCONDUCTIVITY
*TANTALUM ALLOYS-- SUPERCONDUCTIVITY
CRITICAL FIELD
MEAN FREE PATH
N66200* --Physics (Low Temperature)--Superconductivity
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE