Structural features, nonstoichiometry and high-temperature transport in SrFe{sub 1-x}Mo{sub x}O{sub 3-{delta}}

Journal Article · Wed Apr 15 04:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.12.026· OSTI ID:21370340

Markov, A A ^[1]; Savinskaya, O A ^[2]; Nemudry, A P ^[2]; Leonidov, I A ^[1]; Pavlyukhin, Yu T ^[2]; Ishchenko, A V ^[3]; Kozhevnikov, V L ^[1]

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1. Institute of Solid State Chemistry, UB RAS, 91 Pervomaiskaya Str., 620219 Ekaterinburg (Russian Federation)
2. Institute of Solid State Chemistry and Mechanochemistry, SB RAS, 18 Kutateladze Str., 630128 Novosibirsk (Russian Federation)
3. Boreskov Institute of Catalysis, SB RAS, 5 Lavrentiev Ave., 630090 Novosibirsk (Russian Federation)

The oxide solid solutions SrFe{sub 1-x}Mo{sub x}O{sub 3-{delta}}, where x=0.05, 0.1 and 0.2, are studied in this work. It is shown that substitution of iron for molybdenum results in stabilization of a cubic quasi-perovskite locally inhomogeneous structure, which is evidenced by HREM and Moessbauer spectroscopy. The coulometric titration is used in order to determine changes of oxygen nonstoichiometry in the obtained solutions with temperature and ambient oxygen partial pressure. Partial molar thermodynamic functions of the labile oxygen are calculated from the measured data. The variations of partial molar entropy with oxygen content follow the ideal gas model reasonably well thus demonstrating approximately random distribution of oxygen vacancies in the doped ferrite at high temperatures. The partial molar enthalpy is found to increase with doping, which is indicative of a progressive decrease in average values of the bonding energy of labile oxygen ions. The measurements of total conductivity are used in order to determine partial contributions of charge carriers. The oxygen ion component is shown to increase at small level of doping, x=0.05 while further increase in molybdenum content is accompanied with the decline in the ion conductivity. The electron contribution in reducing conditions tends to increase with molybdenum content, which is interpreted as a manifestation of involvement of Mo{sup 5+} cations in electron transport. Concentration and mobility of electron carriers are calculated. Some increase in mobility of electron holes at small doping is explained as related to the filling of oxygen vacancies. - Graphical abstract: An electron conductivity in SrFe{sub 1-x}Mo{sub x}O{sub 3-{delta}} in reducing conditions.

• OSTI ID: 21370340
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 4 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALINE EARTH METAL COMPOUNDS
CHARGED PARTICLES
CHEMICAL ANALYSIS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISPERSIONS
DOPED MATERIALS
ELECTRON MICROSCOPY
ELECTRON MOBILITY
ELEMENTS
ENTHALPY
ENTROPY
HOMOGENEOUS MIXTURES
IONS
IRON COMPOUNDS
MATERIALS
MICROSCOPY
MIXTURES
MOBILITY
MOLYBDATES
MOLYBDENUM COMPOUNDS
MOLYBDENUM IONS
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
OXYGEN IONS
PARTICLE MOBILITY
PHYSICAL PROPERTIES
POINT DEFECTS
QUANTITATIVE CHEMICAL ANALYSIS
REFRACTORY METAL COMPOUNDS
SOLID SOLUTIONS
SOLUTIONS
STRONTIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TITRATION
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
VACANCIES
VOLTAMETRY
VOLUMETRIC ANALYSIS