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Tunneling measurements on spin-paired superconductors with spin-orbit scattering

Journal Article · · Physical Review, B: Solid State

Electron spin effects in superconducting Al films were studied by measuring the conductance of tunnel junctions in a magnetic field. Superconductor--normal-metal tunnel junctions were made with 50-A-thick Al and 500--1000-A-thick Ag films with Al$sub 2$$O$$sub 3$ as the barrier. The measured conductance curves were fit by theoretical calculations, which included depairing effects and spin-orbit scattering, and values of the depairing parameter zeta$sub 0$ and the spin-orbit parameter b$sub 0$ were obtained. The relation zeta(0) + CH$sup 2$/DELTA$sub 0$ was found to describe the (parallel) magnetic field dependence of the depairing. The values of b$sub 0$ obtained were independent of H. Superconductor-superconductor tunnel junctions made with two 50-A-thick Al films were studied with various amounts of Ge and Mn impurities. The Ge impurity simply raised T/sub c/, whereas the Mn lowered T/sub c/ and increased b$sub 0$. The approximate dependence of b$sub 0$ on the Mn impurity concentration was obtained. The qualitative features for spin-orbit scattering predicted by theory were observed, and spin-flip scattering in the tunneling process was shown to be negligible.

Research Organization:
Massachusetts Inst. of Tech., Cambridge
Sponsoring Organization:
USDOE
NSA Number:
NSA-33-006017
OSTI ID:
4173824
Journal Information:
Physical Review, B: Solid State, Journal Name: Physical Review, B: Solid State Journal Issue: 11 Vol. 11; ISSN 0556-2805; ISSN PRBMDO
Country of Publication:
United States
Language:
English