Influence of the Microstructure on the High-Temperature Transport Properties of GdBaCo2O5.5+δ Epitaxial Films

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• 作者：Mnica Burriel ; Montse Casas-Cabanas ; James Zapata ; Haiyan Tan ; Jo Verbeeck ; Cecilia Sols ; Jaume Roqueta ; Stephen J. Skinner ; John A. Kilner ; Gustaaf Van Tendeloo ; Jose Santiso
• 刊名：Chemistry of Materials
• 出版年：2010
• 出版时间：October 12, 2010
• 年：2010
• 卷：22
• 期：19
• 页码：5512-5520
• 全文大小：1128K
• 年卷期：v.22,no.19(October 12, 2010)
• ISSN：1520-5002

文摘

Epitaxial thin films of GdBaCo₂O_5.5+δ (GBCO) grown by pulsed laser deposition have been studied as a function of deposition conditions. The variation in film structure, domain orientation, and microstructure upon deviations in the cation composition have been correlated with the charge transport properties of the films. The epitaxial GBCO films mainly consist of single- and double-perovskite regions that are oriented in different directions depending on the deposition temperature. Additionally, cobalt depletion induces the formation of a high density of stacking defects in the films, consisting of supplementary GdO planes along the c-axis of the material. The presence of such defects progressively reduces the electrical conductivity. The films closer to the stoichiometric composition have shown p-type electronic conductivity at high pO₂ with values as high as 800 S/cm at 330 °C in 1 atm O₂, and with a pO₂ power dependence with an exponent as low as 1/25, consistent with the behavior reported for bulk GBCO. These values place GBCO thin films as a very promising material to be applied as cathodes in intermediate temperature solid oxide fuel cells.