The specific conductivity, log[σT], and thermal electromotive force coefficient, QT, of this perovskite-like cobaltite were measured at 1173 to 1323K, with PO2 between 10−8 and 1atm. The PO2-T-δ phase diagram of solid LaCoO3-δ was used to change the electrical property data into log[σT]-δ and QT-δ dependences. The iso-concentration temperature dependences of the specific conductivity [logσ]δ-1/T and Seebeck coefficient Qδ-1/T for were analyzed. It was concluded that the charge transfer was activated in nature and had a low activation energy. This provided evidence that small-radius polarons (CoCo•, CoCo’) were responsible for charge transfer in this perovskite-like material. The calculated equilibrium constants for the formation of electronic defects and the functional dependences of defect concentration [CoCo•]T = f1(δ) and [CoCo’]T = f2(δ) were used to analyze the polaron transfer parameters.

Equilibrium of Point Defects and Charge Transfer in Lanthanum Cobaltite. A.N.Petrov, A.Y.Zuev, A.I.Vylkov, D.S.Tsvetkov: Russian Journal of Physical Chemistry A, 2006, 80[1], S128-33