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The nature of iron-oxygen vacancy defect centers in PbTiO3

H. Mestric·R. -A. Eichel·T. Kloss·K. -P. Dinse·So. Laubach·St. Laubach·P. C. Schmidt·K. A. Schoenau·M. Knapp·H. Ehrenberg
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Abstract

The iron(III) center in ferroelectric PbTiO3 together with an oxygen vacancy forms a charged defect associate, oriented along the crystallographic c-axis. Its microscopic structure has been analyzed in detail comparing results from a semi-empirical Newman superposition model analysis based on finestructure data and from calculations using density functional theory. Both methods give evidence for a substitution of Fe3+ for Ti4+ as an acceptor center. The position of the iron ion in the ferroelectric phase is found to be similar to the B-site in the paraelectric phase. Partial charge compensation is locally provided by a directly coordinated oxygen vacancy. Using high-resolution synchrotron powder diffraction, it was verified that lead titanate remains tetragonal down to 12 K, exhibiting a c/a-ratio of 1.0721.

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H. Mestric, R. -A. Eichel, T. Kloss, K. -P. Dinse, So. Laubach, St. Laubach, P. C. Schmidt, K. A. Schoenau, M. Knapp, H. Ehrenberg. 2005-04-27. The nature of iron-oxygen vacancy defect centers in PbTiO3. https://doi.org/10.1103/physrevb.71.134109

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