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Defect structure in aliovalently-doped and isovalently-substituted PbTiO3nano-powders

Erdem, Emre and Jakes, Peter and Parashar, S. K. S. and Kiraz, Kamil and Somer, Mehmet and Rüdiger, Andreas and Eichel, Rüdiger-A. (2010):
Defect structure in aliovalently-doped and isovalently-substituted PbTiO3nano-powders.
In: Journal of Physics: Condensed Matter, pp. 345901-1, 22, (34), ISSN 0953-8984, [Online-Edition: http://dx.doi.org/10.1088/0953-8984/22/34/345901],
[Article]

Abstract

The defect structure of Fe3 + -, Cu2 + -, Mn4 + - and Gd3 + -doped PbTiO3 nano-powders has been studied by electron paramagnetic resonance (EPR) spectroscopy. Analogous to the situation for 'bulk' ferroelectrics, Fe3 + and Cu2 + act as acceptor-type functional centers that form defect complexes with charge-compensating oxygen vacancies. The corresponding defect dipoles are aligned along the direction of spontaneous polarization, PS, and possess an additional defect polarization, PD. Upon the transition to the nano-regime, the defect structure is modified such that orientations perpendicular to PS, (FeTi'–V0°°)°_ and (Cu''Ti-V0°°)_* also become realized. Moreover, the binding energy for the defect complexes is lowered such that instead 'free' FeTi' and V0°°-centers are formed. As a consequence, the concentration of mobile V0°° that enhances the ionic conductivity through drift diffusion is increased for the nano-powders. Finally, in the nano-regime the ferroelectric 'hardening' is expected to be considerably decreased as compared to the 'bulk' compounds. In contrast to the acceptor-type dopants, the donor-type Gd3 + dopant is incorporated as an 'isolated' functional center, where charge compensation by means of lead vacancies is performed in distant coordination spheres.

Item Type: Article
Erschienen: 2010
Creators: Erdem, Emre and Jakes, Peter and Parashar, S. K. S. and Kiraz, Kamil and Somer, Mehmet and Rüdiger, Andreas and Eichel, Rüdiger-A.
Title: Defect structure in aliovalently-doped and isovalently-substituted PbTiO3nano-powders
Language: English
Abstract:

The defect structure of Fe3 + -, Cu2 + -, Mn4 + - and Gd3 + -doped PbTiO3 nano-powders has been studied by electron paramagnetic resonance (EPR) spectroscopy. Analogous to the situation for 'bulk' ferroelectrics, Fe3 + and Cu2 + act as acceptor-type functional centers that form defect complexes with charge-compensating oxygen vacancies. The corresponding defect dipoles are aligned along the direction of spontaneous polarization, PS, and possess an additional defect polarization, PD. Upon the transition to the nano-regime, the defect structure is modified such that orientations perpendicular to PS, (FeTi'–V0°°)°_ and (Cu''Ti-V0°°)_* also become realized. Moreover, the binding energy for the defect complexes is lowered such that instead 'free' FeTi' and V0°°-centers are formed. As a consequence, the concentration of mobile V0°° that enhances the ionic conductivity through drift diffusion is increased for the nano-powders. Finally, in the nano-regime the ferroelectric 'hardening' is expected to be considerably decreased as compared to the 'bulk' compounds. In contrast to the acceptor-type dopants, the donor-type Gd3 + dopant is incorporated as an 'isolated' functional center, where charge compensation by means of lead vacancies is performed in distant coordination spheres.

Journal or Publication Title: Journal of Physics: Condensed Matter
Volume: 22
Number: 34
Divisions: DFG-Collaborative Research Centres (incl. Transregio)
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > B - Characterisation > Subproject B1: EPR-Investigations of defects in ferroelectric ceramic material
Date Deposited: 08 Aug 2011 09:20
Official URL: http://dx.doi.org/10.1088/0953-8984/22/34/345901
Additional Information:

SFB 595 B1

Identification Number: doi:10.1088/0953-8984/22/34/345901
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