High-temperature electrical conductivity and thermopower in nonstoichiometric La1-xSrxCoO3-δ (x = 0.6)

E. B. Mitberg, M. V. Patrakeev, I. A. Leonidov, V. L. Kozhevnikov*, K. R. Poeppelmeier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


From 650 to 900°C in situ conductivity and thermopower measurements it was determined that La1-xSrxCoO3-δ (x = 0.6) is a small polaron conductor over the range 0.12 < δ < 0.38 with a hopping energy of approximately 0.08 eV. Cobalt's valence distribution was calculated from the thermopower data complemented with the site balance and electroneutrality relations. Three valence states of cobalt appear to be present with the equilibrium constant of disproportionation, 2Co3+ = Co2+ + Co4+ independent of temperature and dependent of oxygen content. As δ decreases, a p-to-n transition occurs indicating a near half-filling of the conductance band. It is concluded also that the simple polaronic description of conductance becomes insufficient when approaching the stoichiometric oxygen composition.

Original languageEnglish (US)
Pages (from-to)325-330
Number of pages6
JournalSolid State Ionics
Issue number3-4
StatePublished - May 2 2000


  • Cobaltite
  • Electron conductivity
  • Mixed conductor
  • Thermopower

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics


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