Defect processes in orthorhombic LnBaCo2O5.5 double perovskites

文献情報

出版日 2011-07-18

DOI 10.1039/C1CP21471C

インパクトファクター 3.676

著者

I. D. Seymour, A. Chroneos, J. A. Kilner, R. W. Grimes

原文を見る

要旨

Static atomistic simulations based on the Born model were used to investigate intrinsic defect processes in orthorhombic LnBaCo2O5.5 (Ln = Y, La, Pr, Nd, Sm, Gd, Dy, Ho, Er, and Yb) double perovskites. It was found that Ln/Ba antisite disorder is the lowest energy defect reaction, with the large Ln cations giving rise to smaller antisite energies. On the oxygen sublattice the oxygen Frenkel disorder dominates and also decreases in energy with increasing Ln cation size. The lowest energy oxygen vacancy and interstitial positions are in the LnO0.5 and CoO2 layers respectively. Interestingly, the calculations indicate that oxygen vacancies cluster with Ba antisite defects (occupying Ln sites). This suggests that the transport of oxygen vacancies will be influenced not only by the oxygen Frenkel energy but also the antisite energy. We propose that PrBaCo2O5.5 most efficiently balances these two competing effects as it has an oxygen Frenkel energy of just 0.24 eV per defect combined with a high antisite energy (0.94 eV), which ensures that the A cation sublattice will remain more ordered.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

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