Microstructural aspects of the ionic transport properties of strontium-substituted lanthanum cobaltites

W. Sitte*, E. Bucher, W. Preis, I. Papst, W. Grogger, F. Hofer

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

Abstract

The ionic conductivity and microstructure of selected compositions of the solid solution La1-xSrxCoO3-δ (LSC) were examined with respect to possible vacancy ordering phenomena. Homogeneous samples of LSC were prepared by the glycine nitrate process. The ionic conductivity was obtained as a function of the oxygen partial pressure (-3.5 ≤ log[p(O2)/atm] ≤ 0.5) using a recently developed galvanostatic polarization technique. At 825°C the p(O2)-dependence of the ionic conductivity of La1-xSrxCoO3-δ (x = 0.4 and 0.6) shows a distinct maximum. Although this behavior has yet to be explained unambiguously it is indicative of decreasing mobility of ionic charge carriers, e.g. due to cooperative vacancy ordering. From the temperature dependence of the ionic conductivity of La1-xSrxCoO3-δ (x = 0.6) activation energies at constant nonstoichiometry (0.20 ≤ δ ≤ 0.28) were obtained. As vacancy association and microstructure are presumed to play a significant role we combined the results of ionic conductivity measurements and electron microscopical investigations. HRTEM images revealed a superstructure within microdomains of about 100 nm in size.

Original languageEnglish
Pages (from-to)527-532
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Volume756
DOIs
Publication statusPublished - 25 Jul 2003
EventSolid State Ionics 2002 - Boston MA, United States
Duration: 2 Dec 20025 Dec 2002

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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