NbN materials development for practical superconducting devices

Conference · Tue Jan 01 04:00:00 EST 1980

OSTI ID:6454059

Kampwirth, R T; Gray, K E

Power switches such as a Superconducting Fault Current Limiter require large cross sectional area superconductors with both high critical current density J/sub c/ and normal state resistivity rho/sub n/. Large values of J/sub c/ and rho/sub n/ have been previously reported in small cross sectional area weak links of NbN. We report on reactively sputtered NbN films up to 5 ..mu..m thick and 2.2 cm wide which have rho/sub n/ > 200 ..mu cap omega.. cm and a self-field J/sub c/ up to 10/sup 6/ A/cm/sup 2/. Severe degradation in J/sub c/ was observed with increasing film width and for millisecond current pulses. This degradation could be substantially reduced by stabilization with either low rho/sub n/ normal metal or the use of a sapphire substrate. The resistivity and critical current dependence both imply Josephson coupled grains and the results will be discussed within that model.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6454059
• Report Number(s): CONF-800980-38; ON: DE81023891
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CRITICAL CURRENT
CURRENT DENSITY
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
EQUIPMENT
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
PNICTIDES
SAMPLE PREPARATION
SUBSTRATES
SUPERCONDUCTORS
SWITCHES
TRANSITION ELEMENT COMPOUNDS