Defect processes in orthorhombic LnBaCo2O5.5 double perovskites

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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

64 Citations (Scopus)


Static atomistic simulations based on the Born model were used to investigate intrinsic defect processes in orthorhombic LnBaCo2O 5.5 (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.

Original languageEnglish
Pages (from-to)15305-15310
Number of pages6
JournalPhysical Chemistry Chemical Physics
Issue number33
Publication statusPublished - 7 Sep 2011


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