Some temperature-dependent properties of niobium tunnel junctions

Journal Article · Wed Dec 01 04:00:00 EST 1976 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.322573· OSTI ID:7262198

Broom, R F

Some measurements of the electrical properties of Nb tunnel junctions in the temperature range 2 to 9/sup 0/K are described. These include (1) the quasiparticle tunneling current, (2) the gap voltage 2..delta../e, (3) the dc Josephson current i/sub 1/, and (4) the London penetration depth lambda. With regard to (1) the tunnel current is well described by an empirical model in which the density of states within the forbidden gap of the top electrode is finite and sharply peaked at the gap edges. This, and the temperature dependence of i/sub 1/, are consistent with the proximity-effect model proposed by Schwidtal to describe Nb-NbO/sub x/-Pb junctions. The temperature and frequency dependences of the penetration depth show fair agreement with the BCS theory in the local ''dirty'' limit. Some results are also given on the variation of junction capacitance with Josephson current density. (AIP)

• Research Organization: IBM Zurich Research Labortoary, 8803 Rueschlikon-ZH, Switzerland
• OSTI ID: 7262198
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 47:12; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BCS THEORY
ELECTRICAL PROPERTIES
ELEMENTS
FABRICATION
FILMS
JOSEPHSON EFFECT
METALS
NIOBIUM
PENETRATION DEPTH
PHYSICAL PROPERTIES
QUASI PARTICLES
REFRACTORY METALS
SUPERCONDUCTING JUNCTIONS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS
TUNNEL EFFECT