Superconducting and normal state properties of hexagonal tungsten bronzes RhWO/sub 3/, Rh/sub 2/, WO/sub 3/ and K/sub x/ WO/sub 3/
Measurements of the resistivity rho, Hall voltage V/sub H/, Seebeck coefficient S, superconducting transition temperature T/sub c/, and the superconducting upper critial field H/sub c2/ were obtained for single crystals of K/sub x/ WO/sub 3/(0.18 < x < 0.33). Concentration-dependent and temperature-dependent transitions were observed similar to those reported for the Rb-HTB. Associated with the temperature-dependent phase transitions are anomalies in the resistivity, Hall coefficient and Seebeck coefficient. The concentration dependence of the onset temperatures of the anomalies showed a maximum near x = 0.25 indicating a phase transition with concentration. Associated with this transition are a suppressed superconducting T/sub c/, a sharp drop in the residual resistivity, a rise in the residual resistance ratio, and a break in the slope of the Seebeck coefficient with temperature. The angular variation of the critical field has been measured for the K-HTB and for hexagonal Rb/sub x/Cs/sub y/WO/sub 3/ with x + y = 0.24. A 6-fold anisotropy in H/sub c2/ was observed in the basal plane. The magnitude of H/sub c2/ was observed to depend on both the concentration and the size of the insertion ion. The resistivity and superconducting T/sub c/ measurements were also obtained on a single-crystals of Rb/sub x/Cs/sub y/WO/sub 3/. The temperature-dependent anomaly was suppressed with relatively small amounts of Cs content. T/sub c/ increased with increasing Cs content for total concentrations x + y = 0.24 and remained nearly constant for x + y = 0.28. The concentration dependence of the superconducting properties of Rb/sub x/WO/sub 3/ was analyzed using two methods.
- Research Organization:
- Florida State Univ., Tallahassee (USA)
- OSTI ID:
- 6167681
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METALS
ALLOYS
CESIUM
COPPER ALLOYS
COPPER BASE ALLOYS
DATA
ELECTRIC CONDUCTIVITY
ELECTRIC POTENTIAL
ELECTRICAL PROPERTIES
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
MAGNETIC FIELDS
METALS
NUMERICAL DATA
PHYSICAL PROPERTIES
POTASSIUM
QUANTITY RATIO
RUBIDIUM
SUPERCONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
TUNGSTEN ALLOYS
TUNGSTEN BRONZE