Hopping conduction in a mixed valence oxide system: Pr/sub 1-y/Gd/sub y/O/sub 1. 5+delta/
Journal Article
·
· J. Solid State Chem.; (United States)
The electrical conductivity of sigma-phase Pr/sub 1-y/Gd/sub y/O/sub 1.5 + delta/ (y = 0.0, 0.1, and 0.4) was measured as a function of temperature and oxygen partial pressure. The dependence of the electrical conductivity of Pr/sub 1-y/Gd/sub y/O/sub 1.5 + delta/ on the composition was determined by combining gravimetric and conductivity data. The results are consistent with the small-polaron model of localized charge carriers hopping between two adjacent Pr ions in different valence states. The following equation was quantitatively examined: sigma = ns(1-s)pk/sub h/, where n is the concentration of total Pr ions, s is the fraction of Pr/sup 4 +/ ions in total Pr ions, p is the probability that cationic positions are occupied by mixed valence ions, and k/sub h/ is a constant characteristic of the charge-transfer process between different valence states. It was found that k/sub h/ increases slightly with increasing delta. This dependence is discussed in terms of the observed activation energy and the degree of delocalization of the 4f electrons.
- Research Organization:
- Tokyo Univ.
- OSTI ID:
- 7347561
- Journal Information:
- J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 19:1; ISSN JSSCB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CHARGE CARRIERS
CHEMICAL COMPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EQUATIONS
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARONS
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
PRESSURE DEPENDENCE
QUASI PARTICLES
RARE EARTH COMPOUNDS
STOICHIOMETRY
TEMPERATURE DEPENDENCE
VALENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CHARGE CARRIERS
CHEMICAL COMPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EQUATIONS
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARONS
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
PRESSURE DEPENDENCE
QUASI PARTICLES
RARE EARTH COMPOUNDS
STOICHIOMETRY
TEMPERATURE DEPENDENCE
VALENCE