Thermodynamic quantities and defect equilibrium in the perovskite-type oxide solid solution La/sub 1-x/Sr/sub x/FeO/sub 3-delta/

Journal Article · Sun Mar 01 00:00:00 EST 1987 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(87)90331-8· OSTI ID:6507545

Mizusaki, J; Yoshihiro, M; Yamauchi, S; Fueki, K

In order to clarify the relationship between the thermodynamic quantities and the defect equilibrium of the solid solution La/sub 1-x/Sr/sub x/FeO/sub 3-delta/, analysis and statistical thermodynamic calculations were made using the authors' previously reported nonstoichiometry data. From the delta-log P/sub O/sub 2//-T relationships, using the Gibbs-Helmholtz equation, the partial molar enthalpy (h/sub 0/ - H/sup 0//sub 0/) and the partial molar entropy (s/sub 0/ - s/sup 0//sub 0/) of oxygen in La/sub 1-x/Sr/sub x/FeO/sub 3-delta/ were determined as functions of x and delta. Here, the standard states of h/sub 0/ and s/sub 0/, h/sup 0//sub 0/, and s/sup 0//sub 0/ are in equilibrium with 1 atm oxygen gas. For delta < x/2 and delta > x/2, (h/sub 0/ - h/sup 0//sub 0/) is essentially constant and (s/sub 0/ - s/sup 0//sub 0/) increases with delta. Around delta = x/2, drastic decreases in (h/sub 0/ - h/sup 0//sub 0/) and (s/sub 0/ - s/sup 0//sub 0/) are observed. The calculated relationships based on the statistical thermodynamic model agreed quite well with those determined from the experimental data using the Gibbs-Helmholtz equation.

• Research Organization: Univ. of Tokyo, Japan
• OSTI ID: 6507545
• Journal Information: J. Solid State Chem.; (United States), Vol. 67:1
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
IRON OXIDES
CRYSTAL DEFECTS
THERMODYNAMIC PROPERTIES
LANTHANUM OXIDES
STRONTIUM OXIDES
SOLID SOLUTIONS
STATISTICAL MODELS
THEORETICAL DATA
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
DATA
DISPERSIONS
INFORMATION
IRON COMPOUNDS
LANTHANUM COMPOUNDS
MATHEMATICAL MODELS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SOLUTIONS
STRONTIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)