Capacitance measurement of Josephson tunnel junctions with microwave-induced dc quasiparticle tunneling currents

Journal Article · Sat May 01 04:00:00 EDT 1982 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.331107· OSTI ID:5582549

Hamasaki, K; Yoshida, K; Irie, F; Enpuku, K

The microwave response of the dc quasiparticle tunneling current in Josephson tunnel junctions, where the Josephson current is suppressed by an external magnetic field, has been studied quantitatively in order to clarify its characteristics as a probe for the measurement of the junction capacitance. Extensive experiments for both small and long junctions are carried out for distinguishing between microwave behaviors of lumped and distributed constant junctions. It is shown that the observed voltage dependence of the dc quasiparticle tunneling current modified by an applied rf field is in good agreement with a theoretical result which takes into account the influence of the microwave circuit connected to the junction. The comparison between theory and experiment gives the magnitude of the internal rf field in the junction. Together with the applied rf field, this internal rf field leads to the junction rf impedance which is dominated by the junction capacitance in our experimental condition. In the case of lumped junctions, this experimental rf impedance is in reasonable agreement with the theoretical one with the junction capacitance estimated from the Fiske step of the distributed junction fabricated on the same substrate; the obtained ratio of the experimental impedance to the theoretical one is approximately 0.6--1.7. In the case of distributed junctions, however, experimental values of their characteristic impedances are approximately 0.2--0.3 of theoretical values calculated by assuming the one-dimensional junction model and taking account of the standing-wave effect in the junction.

• Research Organization: Department of Electrical Engineering, Technological University of Nagaoka, Nagaoka 949-54, Japan
• OSTI ID: 5582549
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Journal Issue: 5 Vol. 53:5; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPARATIVE EVALUATIONS
CURRENTS
DATA
DIRECT CURRENT
ELECTRIC CURRENTS
ELECTROMAGNETIC RADIATION
INFORMATION
JOSEPHSON JUNCTIONS
JUNCTIONS
MAGNETIC FIELDS
MATHEMATICAL MODELS
MICROWAVE RADIATION
NUMERICAL DATA
ONE-DIMENSIONAL CALCULATIONS
PROBES
QUASI PARTICLES
RADIATION EFFECTS
RADIATIONS
SUPERCONDUCTING JUNCTIONS
THEORETICAL DATA
TUNNEL EFFECT