Interpretation of the Co K-edge EXAFS in LaCoO₃ using molecular dynamics simulations

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• 作者：A. Kuzmin^a ; ^{a.kuzmin@cfi.lu.lv} ; ; V. Efimov^b ; E. Efimova^b ; V. Sikolenko^c ; S. Pascarelli^d ; I.O. Troyanchuk^e
• 关键词：LaCoO₃ ; EXAFS ; Co K-edgep ; Molecular dynamics ; Thermal disorder
• 刊名：Solid State Ionics
• 出版年：2011
• 出版时间：22 April 2011
• 年：2011
• 卷：188
• 期：1
• 页码：21-24
• 全文大小：589 K

文摘

Temperature dependent (180–400 K) Co K-edge EXAFS spectra from perovskite-type rhombohedral () LaCoO₃ have been successfully interpreted using a combination of classical NVT molecular dynamics (MD) and ab initio multiple-scattering (MS) theory. The method allowed us to account entirely for thermal disorder and to interpret reliably the contribution from the coordination shells beyond the first one into the total EXAFS spectrum taking into account many-body effects. The best agreement between experimental and configuration-averaged EXAFS spectra was obtained for pure ionic La³⁺ and partially ionic Co^1.35+ and O^1.45− charges indicating the mixed ionic-covalent character of the Co―O bonds.