The Fe K-edge X-ray absorption characteristics of La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} prepared by solid state reaction
- Energy and Material Research Consulting, Vigolo del Maglio, CH-6648 Minusio, TI (Switzerland)
- Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for High Performance Ceramics, CH-8600 Duebendorf (Switzerland)
- Brookhaven National Laboratory, Chemistry Department, Upton, NY 11973 (United States)
Perovskites of the composition La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (x = 0.0, 0.1, 0.5, 0.9, 1.0) were prepared by the conventional solid state reaction route. The single phase behaviour was assessed by XRD analysis, the electronic properties were investigated by Fe K-edge X-ray absorption spectroscopy. The work is focused on the valence state of iron and the oxygen vacancies of the perovskites investigated. The XRD measurements revealed that the solid state reaction yields cubic perovskites for x = 1, 0.9, rhombohedral perovskites for x = 0.5, and orthorhombic perovskites for x = 0, 0.1. The X-ray absorption data are discussed in detail with respect to Fe K-edge shift, white-line intensity, pre-edge features, and the EXAFS data. The first peak in the Fourier transform of the Chi x k{sup 3} and Chi x k{sup 2} functions was simulated for a detailed analysis of scattering contributions from the first oxygen shell to evaluate the Fe-O bond length. The substitution of lanthanum by strontium leads to a corresponding increase of the iron valence state and thus to the formation of the Jahn-Teller Fe{sup 4+} ion. This is causing disorder in the first coordination shell and thus an increase of the Debye-Waller factor with increasing x. The Fe-O bond length obtained from XRD and especially from X-ray absorption data are consistent with {delta}-values close to zero.
- OSTI ID:
- 22029792
- Journal Information:
- Materials Research Bulletin, Vol. 44, Issue 6; Other Information: Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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