Microwave impedance of superconducting weak links

Journal Article · Thu Jul 01 04:00:00 EDT 1976 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.323124· OSTI ID:7353014

Franson, J D; Mercereau, J E

Calibrated measurements of both the real and imaginary parts of the microwave impedance of proximity coupled superconducting weak links have been made. The measurements were compared with analytic calculations based on several different models for the supercurrent I/subs/ and quasiparticle current. For dc bias currents I/sub 1/ less than the critical current I/subc/, the experimental results are consistent with the Josephson relation I/subs/=I/subc/ sinphi, where phi is the quantum phase angle. However, for I/sub 1/>I/subc/, the Fourier component of I/subs/ at the Josephson frequency is found to be significantly less (approx.0.65 +- 0.1) than would be predicted from I/subs/=I/subc/ sinphi, and consistent with Tinkham's analysis of a phase slip process. The experimental results indicate that the phase-dependent part of the quasiparticle current, if it exists at all, is no more than 10% of the total quasiparticle current. These results do not necessarily contradict previous measurements made on true tunnel junctions because of the fundamental differences between the two types of devices. (AIP)

• Research Organization: Low Temperature Physics 63-37, California Institute of Technology, Pasadena, California 91125
• OSTI ID: 7353014
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 47:7; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAVITY RESONATORS
CRITICAL CURRENT
CURRENTS
ELECTRIC BRIDGES
ELECTRIC CURRENTS
ELECTRIC IMPEDANCE
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
ELEMENTS
EQUIPMENT
FILMS
IMPEDANCE
JOSEPHSON EFFECT
JOSEPHSON JUNCTIONS
METALS
MICROWAVE RADIATION
QUASI PARTICLES
RADIATIONS
REFRACTORY METALS
SUPERCONDUCTING JUNCTIONS
TANTALUM
TRANSITION ELEMENTS
TUNGSTEN
TUNNEL EFFECT