Superconducting tunneling into the A15 Nb/sub 3/Al thin films

Journal Article · Wed Apr 01 04:00:00 EST 1981 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.23.3230· OSTI ID:6584870

Kwo, J; Geballe, T H

Single-particle (Giaever) tunneling has been performed on A15 Nb/sub 3/Al thin films with good-quality junctions formed by oxidized amorphous-silicon barriers. The tunneling measurement is used as a diagnostic probe for assessing the material properties of Nb/sub 3/Al, including changes in the progressive film growth. The electron-phonon spectral function a/sup 2/F(w) and related physical parameters are generated by the proximity-effect inversion analysis of the tunneling density of states. We find that Nb/sub 3/Al is a strong-coupled superconductor with 2D/k/sub B/T/sub c/> or =4.4 only when the composition approaches the A15 phase boundary (24 at. % Al). A difference in the low-frequency behavior of a/sup 2/F(w), observed between two junctions of different coupling strength, strongly suggests the importance of a mode softening mechanism, and implies that the average 's are rather sensitive to composition, or perhaps disorder. The lattice of Nb/sub 3/Al being softer than Nb/sub 3/Sn and V/sub 3/Si contributes significantly to the large l and the high T/sub c/ of Nb/sub 3/Al.

• Research Organization: Department of Applied Physics, Stanford University, Stanford, California 94305
• OSTI ID: 6584870
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 23:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ALUMINIUM ALLOYS
BETA-W LATTICES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELECTRON-PHONON COUPLING
FILMS
INTERMETALLIC COMPOUNDS
JUNCTIONS
NIOBIUM ALLOYS
NIOBIUM BASE ALLOYS
PENETRATION DEPTH
PHYSICAL PROPERTIES
PROXIMITY EFFECT
QUANTITY RATIO
SUPERCONDUCTING FILMS
SUPERCONDUCTING JUNCTIONS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
TUNNEL EFFECT