The nature of iron-oxygen vacancy defect centers in PbTiO3

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.

11 pages, 5 figures, accepted in Phys. Rev. B

References in corpus (7)

• Phase transitions in BaTiO${}_3$ from first principles
• The physics of dynamical atomic charges: the case of ABO3 compounds
• Ab initio study of ferroelectric domain walls in PbTiO3
• Ab initio statistical mechanics of the ferroelectric phase transition in PbTiO3
• A first-principles study of oxygen vacancy pinning of domain walls in PbTiO3
• First-principles study of stability and vibrational properties of tetragonal PbTiO_3
• High-frequency electron paramagnetic resonance investigation of the Fe3+ impurity center in polycrystalline PbTiO3 in its ferroelectric phase

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• Multiscale Simulations of Defect Dipole-Enhanced Electromechanical Coupling at Dilute Defect Concentrations
• Double polarization hysteresis loop induced by the domain pinning by defect dipoles in HoMnO3 epitaxial thin films
• Local atomic geometry and Ti 1s near-edge spectra in PbTiO${}_3$ and SrTiO${}_3$
• Improving the Functional Control of Aged Ferroelectrics using Insights from Atomistic Modelling
• Investigations of the g factors and local structure for orthorhombic Cu^{2+}(1) site in fresh PrBa_{2}Cu_{3}O_{6+x} powders