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

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

OSTI ID:5790378

Hakimi, M

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
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ACTINIDE ALLOYS
ALLOYS
CERIUM ALLOYS
CHEMICAL COMPOSITION
COBALT ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
IRIDIUM ALLOYS
IRON ALLOYS
LANTHANUM ALLOYS
NICKEL ALLOYS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
PRESSURE DEPENDENCE
RARE EARTH ALLOYS
RUTHENIUM ALLOYS
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
THORIUM ALLOYS
TRANSITION TEMPERATURE