Properties of superconducting thin-film microbridges

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1978

OSTI ID:5092632

Pei, S S

This work reports investigations upon the dependences of critical current and current phase relation on the dimensions of a superconducting thin-film microbridge. A model has been developed upon the Volkov's hyperbolic bridges and the Zaitsev's boundary conditions to calculate the spatial variation of the order parameter for given bridge dimensions. The results indicate that the rigid boundary conditions are good approximations to narrow bridges (W much less than L) only. The critical current density of the bridge has been calculated also as a function of the bridge dimensions. It is found that the critical current density of small bridges is enhanced above its mean field critical value due to the proximity effects of the banks. Very good agreement is found between the calculated enhancement of the critical current density and the experimental results. Direct measurements have been made on the current phase relation of indium bridges with width smaller than 0.6 ..mu..m. The difficulties due to the extra phase shifts from the series thin film electrodes are overcome by a specially designed double loop configuration which has an extra low effective inductance. It is found that the current phase relation of small bridges (W,L, < xi) is sinusoidal. When either one of the bridge dimensions becomes larger than xi, the current phase curve is screwed to the right. For narrow bridges with L > xi, the results agree with the predictions of rigid boundary calculations as expected by our model.

• Research Organization: State Univ. of New York, Stony Brook (USA)
• OSTI ID: 5092632
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104 -- Metals &amp; Alloys-- Physical Properties
656102* -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
&amp; Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOUNDARY CONDITIONS
CRITICAL CURRENT
CURRENT DENSITY
CURRENTS
DATA
DIMENSIONS
ELECTRIC BRIDGES
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
EXPERIMENTAL DATA
FILMS
INDIUM
INFORMATION
JOSEPHSON JUNCTIONS
JUNCTIONS
MATHEMATICAL MODELS
METALS
NOISE
NUMERICAL DATA
ORDER PARAMETERS
PHASE SHIFT
SUPERCONDUCTING FILMS
SUPERCONDUCTING JUNCTIONS
THEORETICAL DATA
TIN