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http://hdl.handle.net/10773/20033
Title: | Phase separation-promoted ion conduction in SrFe0.67Ta0.33O3 (-) (delta) ceramics |
Author: | Patrakeev, M. V. Markov, A. A. Shalaeva, E. V. Tyutyunnik, A. P. Tsipis, E. V. Waerenborgh, J. C. Kharton, V. V. Leonidov, I. A. Kozhevnikov, V. L. |
Keywords: | OXYGEN NONSTOICHIOMETRY MOSSBAUER-SPECTROSCOPY MIXED CONDUCTIVITY PEROVSKITE TEMPERATURE TRANSPORT OXIDATION FERRITES VALENCES OXIDES |
Issue Date: | 2013 |
Publisher: | ELSEVIER SCIENCE BV |
Abstract: | The electrical conductivity of SSrFe0.67Ta0.33O3 (-) (delta) measured in the oxygen partial pressure range from 10-2 to 0.5 atm at 700-950 degrees C, exhibits an anomalous and reversible increase in moderately reducing atmospheres, substantially contributed by oxygen ion transport. The coulometric titration studies in combination with the electron and X-ray diffraction analyses show that this trend correlates with the separation of oxygen-deficient disordered cubic perovskite and Ta-rich double perovskite domains of nanometer-scale size. Mossbauer spectroscopy demonstrated that the predominant state of iron cations in the vicinity of this transition is trivalent Further reduction leads to the formation of Fe2+ states responsible for increasing n-type electronic conductivity, whilst no traces of wustite or oxygen vacancy-ordered brownmillerite phases were detected. The ion conduction in partially reduced SrFe0.67Ta0.33O3 (-) (delta) is significantly higher compared to SrFe0.7Ta0.3O3 (-) (delta) and SrFe0.6Ta0.4O3 (-) (delta) under similar conditions, which may indicate an important role of the interfacial boundary enlarged due to the perovskite phase separation. 0 2013 Elsevier B.V. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/20033 |
DOI: | 10.1016/j.ssi.2013.05.001 |
ISSN: | 0167-2738 |
Publisher Version: | 10.1016/j.ssi.2013.05.001 |
Appears in Collections: | CICECO - Artigos |
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