Superconductivity and the structural phase transitions in palladium hydride and palladium deuteride

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1980

OSTI ID:5659419

Standley, R W

The results of two experimental studies of the superconducting transition temperature, T/sub c/, of palladium hydride, PdH/sub x/, and palladium deuteride, PdD/sub x/, are presented. In the first study, the superconducting transition temperature of PdH/sub x/(D/sub x/) is studied as a function of H(D) concentration, x, in the temperature range from 0.2 K to 4 K. In the second study the effect of the order-disorder structural transition associated with the 50 K anomaly on the superconductivity of PdH/sub x/(D/sub x/) is investigated. Samples were quenched to low temperatures in the disordered state, and their transition temperatures measured. The samples were then annealed just below the anomaly temperature and the ordering process followed by monitoring the change in sample resistance. The transition temperatures in the ordered state were then measured. In a PdD/sub 0/ /sub 817/ sample, the formation of a long-range ordered structure in the deuterium sublattice led to a 9.2% reduction in T/sub c/. In a PdH/sub 0/ /sub 837/ sample, the formation of a long-range ordered structure led to a splitting of the superconducting transition, roughly half of the transition being depressed by approx. 9%, the othe half remaining unchanged. In a PdD/sub 0/ /sub 742/ sample, long-range order did not develop, but an enhancement of short-range order occurred, which led to a 7.5% increase in T/sub c/. In all cases the changes in th superconducting transitions were reversible, the transitions reverting to their original values when the samples were again disordered at the end of each run. These results are discussed in the framework of the local structural excitation model proposed by Ngai and Reinecke. In both studies, samples were prepared from Pd foils loaded with H(D) electrolytically. The superconducting transitions were monitored by measurement of the diamagnetic susceptibility of the samples, using an a.c. mutual inductance method.

• Research Organization: Illinois Univ., Urbana (USA)
• OSTI ID: 5659419
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DEUTERIUM
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HYDRIDES
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
PALLADIUM COMPOUNDS
PALLADIUM HYDRIDES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
STABLE ISOTOPES
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS