Structure and transport properties of La<subscript>0.5</subscript>Sr<subscript>0.5−x</subscript>Ca<subscript>x</subscript>FeO<subscript>3−δ</subscript>.
In: Solid State Ionics, Jg. 262 (2014-09-01), S. 672-677
Online
academicJournal
Zugriff:
Effects of calcium doping on the structure, dimensional stability, and mixed oxygen-ion and electron conductivity of perovskite-like La0.5Sr0.5−xCaxFeO3−δ (x =0–0.3) were studied in light of potential membrane applications. The incorporation of relatively small Ca2+ cations into the lanthanum-strontium ferrite lattice decreases unit cell volume, oxygen nonstoichiometry variations and chemical contribution to the thermal expansion in air. These changes correlate with rising tendency to local oxygen-vacancy ordering and the formation of nano-sized domains with the brownmillerite and LaCa2Fe3O8-type lattices, as revealed by electron diffraction. The resultant vacancy trapping, changing domain structure and enlargement of the interfacial boundary area lead to non-linear relationships between the partial ion conductivity and cation composition, while the apparent activation energy for ion transport at temperatures below 900°С remains almost constant, 0.6–0.7eV. The n-type electron contribution to the total conductivity, measured in the oxygen pressure range 10−20–0.5atm at 700–950°С, is also essentially independent of the calcium concentration. [ABSTRACT FROM AUTHOR]
Titel: |
Structure and transport properties of La<subscript>0.5</subscript>Sr<subscript>0.5−x</subscript>Ca<subscript>x</subscript>FeO<subscript>3−δ</subscript>.
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Autor/in / Beteiligte Person: | Chesnokov, K. ; Yu. ; Markov, A.A. ; Patrakeev, M.V. ; Leonidov, I.A. ; Murzakaev, A.M. ; Leonidova, O.N. ; Shalaeva, E.V. ; Kharton, V.V. ; Kozhevnikov, V.L. |
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Zeitschrift: | Solid State Ionics, Jg. 262 (2014-09-01), S. 672-677 |
Veröffentlichung: | 2014 |
Medientyp: | academicJournal |
ISSN: | 0167-2738 (print) |
DOI: | 10.1016/j.ssi.2013.11.050 |
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