L. MOGNI; J. FOULETIER; F. PRADO; A. CANEIRO

JOURNAL OF SOLID STATE CHEMISTRY

ELSEVIER B. V.

Año: 2005 vol. 178 p. 114 - 122

0022-4596

 We report a systematic study of the non-stoichiometry and high-temperature transport properties of the perovskite related mixed conductor Sr3Fe2O6+d. The variation of the oxygen content (6+d) with T and equilibrium oxygen partial pressure (pO2) was obtained by thermogravimetry within the range: 10-5 < pO2 < 1 atm; 400 £ T £ 1100 °C. From the experimental values of the oxygen chemical potential (mO2), the partial molar enthalpy (hO2) and the partial molar entropy (sO2) were determined for the composition range 6.00 < 6+d < 6.55. A simple defect model based on the mass law action assuming localized  charge carriers and oxygen vacancies was used to reproduce the thermodynamic data. Electrical resistivity measurements as a function of pO2 at constant temperature were obtained within the interval 650 £ T £ 1000 ºC. The activation energy values for the electrical transport process at constant oxygen content values were obtained from the combination of electrical conductivity and thermogravimetric data. The electrical transport data are in agreement with the small polaron model.