An investigation of heating effects in the differential resistance of metal-superconductor junctions

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7114600

Caley, C E

A systematic study of heating and high voltage structure in normal metal/superconductor junctions was carried out using a new AC technique developed for the measurement of I-V and dV/dI-V characteristics of low resistance junctions. This technique uses a pulsed voltage ramp to reduce resistive heating in the junction by decreasing the amount of time current flows in the junction. This technique was used to investigate the differential resistance and the effect of heating in distributed point contact junctions between a tinned copper wire and two thin film metal-superconductor bilayers, Ag/Pb, and Ag/Tl[sub 2]Ba[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10] (Ag/Tl 2223). While heating was still observed in the Ag/Pb system, in the high-T[sub c] superconductor junction, Ag/Tl 2223 system no significant heating was seen. The differential resistance peaks in the Ag/Tl 2223 system are quite sensitive to temperature and therefore the location of these peaks acts as a thermometer for the junction. Since the authors observed no change in the location of these resonance peaks as the time the current flowed was varied, the temperature near the junction was shown to be constant to within 0.25 K, even using a DC voltage ramp. No high voltage structure or curvature at high voltages was seen in these junctions above the resonance structure up to the maximum voltage achieved with the Ag/Tl 2223 system, approximately 450 mV. The resonance structure in the differential resistance is therefore due to the presence of the high temperature superconductor and not to heating effects.

• Research Organization: Stanford Univ., CA (United States)
• OSTI ID: 7114600
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
CUPRATES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
HEATING
HIGH-TC SUPERCONDUCTORS
JUNCTIONS
LEAD
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILVER
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS