Measurement of the current-phase relation of a NbN bridge in the non-hysteretic regime using a SQUID

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5701641

Flora, A P

The static current-phase relation, I(phi), was determined by measuring the induced flux as a function of the external field for granular NbN weak links incorporated in a superconducting ring. The measurement was made using a SQUID magnetometer. A temperature independent kinetic inductance was found together with a sinusoidal component resulting in a current-phase relation expressed implicitly in the form phi(i) = 2..pi../PHI/sub 0/ (iL/sub k/) + arcsin(i/i/sub c/). The value of L/sub K/ for these bridges, whose dimensions are from 1-50 ..mu..m in width by 1 ..mu..m in length is approximately 1.2 x 10/sup -10/H. A kinetic inductance of this magnitude is consistent with a model of small grains of superconducting material separated by Josephson barriers. Furthermore, the critical current versus temperature was measured. Although it is more linear than corresponding data taken at microwave frequencies, the magnitudes of the maximum critical currents and normal resistances are similar (20-59 ..mu..a and 25-50..cap omega.. respectively). The linearity of the data may be attributable to flux flow.

• Research Organization: Virginia Univ., Charlottesville (USA)
• OSTI ID: 5701641
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
420201 -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUXMETERS
MAGNETOMETERS
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
REFRACTORY METAL COMPOUNDS
SQUID DEVICES
SUPERCONDUCTING DEVICES
TRANSITION ELEMENT COMPOUNDS