Evidence for Th, Ru and Ir D-band superconductivity in Th/sub 7/X/sub 3/ (X = Fe, Co, Ni and ZRu/sub 2/ and ZIr/sub 3/ (Z = La, Ce, Th) compounds
The nature of superconductivity in Th/sub 7/X/sub 3/ (X = Fe, Co or Ni), XRu/sub 2/ (X = La, Ce or Th) and XIr/sub 3/ (X = La, Ce or Th) compounds was investigated. To this end, measurements of 1) the temperature dependence of the resistivities of the pure binary compounds, 2) the compositional dependence of the superconducting transition temperatures, T/sub c/, of pseudo-binary compounds, and 3) the pressure dependence of the T/sub c/'s of the pure binary and certain pseudo-binary compounds for pressures up to 18 kbar were performed for all three systems. These systems are determined to be d-band superconductors, their d-character being supported by their saturated resistivities at high temperatures and the presence of T/sup 3/ behavior in their low-temperature resistivity data. High-temperature fits to the parallel-resistor model for resistivities are presented. In the Th/sub 7/X/sub 3/ compounds, superconductivity is suggested to be due to the presence of the 6d-bands with the value of T/sub c/ depending on the number of electrons required to fill X 3d-shells. In the XRu/sub 2/'s and XIr/sub 3/'s, Ru 4d-bands and Ir 5d-bands are suggested to be responsible for the superconductivity, the value of T/sub c/ being determined by the number of electrons provided to them by the X (La, Ce, Th) ions. A method is introduced whereby, for the first time, the valence of Ce ions in Ce-containing superconducting compounds may be determined through the superconductivity itself. Using this method, valences of 3.9 and 3.6 are achieved for the Ce ions in CeRu/sub 2/ and CeIr/sub 3/, respectively.
- Research Organization:
- Tufts Univ., Medford, MA (USA)
- OSTI ID:
- 5790378
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
THORIUM ALLOYS
SUPERCONDUCTIVITY
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IRON ALLOYS
NICKEL ALLOYS
CERIUM ALLOYS
IRIDIUM ALLOYS
LANTHANUM ALLOYS
RUTHENIUM ALLOYS
CHEMICAL COMPOSITION
ELECTRIC CONDUCTIVITY
PRESSURE DEPENDENCE
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
ACTINIDE ALLOYS
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ELECTRICAL PROPERTIES
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
RARE EARTH ALLOYS
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360104* - Metals & Alloys- Physical Properties