Electrical conductivity and defect chemistry of BaxSr1 - xCoyFe1 - yO3 - dBaxSr1?xCoyFe1?yO3? perovskites

Yáng, Z.; Harvey, A.S.; Infortuna, A.; Schoonman, J.; Gauckler, L.J.

doi:doi:10.1007/s10008-010-1208-4

Electrical conductivity and defect chemistry of BaxSr1 - xCoyFe1 - yO3 - dBaxSr1?xCoyFe1?yO3? perovskites

Title

Electrical conductivity and defect chemistry of BaxSr1 - xCoyFe1 - yO3 - dBaxSr1?xCoyFe1?yO3? perovskites

Author

Yáng, Z.
Harvey, A.S.
Infortuna, A.
Schoonman, J.
Gauckler, L.J.

Faculty

Applied Sciences

Department

Chemical Engineering

Date

2010-10-15

Abstract

Bulk BaxSr1 - xCoyFe1 - yO3 - dBaxSr1?xCoyFe1?yO3? compositions (BSCF) were synthesized by the solid-state reaction method. The electrical conductivity of ceramic bars was measured using a dc four-probe method as a function of temperature in air up to 970 °C. All compositions showed thermally activated p-type semi-conductivity up to ~450 °C and then a transition to metal-like conductivity. The small-polaron hopping p-type semi-conductivity depends on the oxygen nonstoichiometry, which increases with increasing temperature. Metal-like conductivity is attributed to the overlap of the transition metal d-electron orbitals with the oxygen p-orbitals. Strontium-rich compositions show higher conductivity. The Co/Fe ratio does not influence much the p-type semi-conduction. Iron-rich compositions revealed more metal-like conduction behavior. The degree of overlap between transition metal d-orbitals and oxygen p-orbitals depends on the Ba/Sr as well as on the Co/Fe ratios.

Subject

electrical conductivity
BSCF
mixed ionic and electronic conduction
perovskite
metal-insulator transition
cathode
solid oxide fuel cell
catalysis

To reference this document use:

http://resolver.tudelft.nl/uuid:c32d353f-358c-48ad-a3f2-720656510f4b

DOI

https://doi.org/10.1007/s10008-010-1208-4

Publisher

Springer

ISSN

1432-8488

Source

http://www.springerlink.com/content/4463472w757mh11j/