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Local variations in defect polarization and covalent bonding in ferroelectric Cu2+-doped PZT and KNN functional ceramics at the morphotropic phase boundary

Eichel, Rüdiger-A. and Erünal, Ebru and Drahus, Michael D. and Smyth, Donald M. and van Tol, Johan and Acker, Jérôme and Kungl, Hans and Hoffmann, Michael J. (2009):
Local variations in defect polarization and covalent bonding in ferroelectric Cu2+-doped PZT and KNN functional ceramics at the morphotropic phase boundary.
In: Physical Chemistry Chemical Physics, pp. 8698-8705, 11, (39), ISSN 1463-9076, [Online-Edition: http://dx.doi.org/10.1039/b905642d],
[Article]

Abstract

Cu2+-doped Pb[Zr0.54Ti0.46]O3 (PZT) and Cu2+-doped [K0.5Na0.5]NbO3 (KNN) ferroelectrics with a dopant concentration of 0.25 mol% were investigated by means of multi-frequency and multi-pulse electron paramagnetic resonance (EPR) spectroscopy. Through the use of high magnetic fields and pulsed microwave fields an enhanced resolution was achieved yielding valuable information about the structural distortion at the dopant site. The results obtained suggest that Cu2+ substitutes for both systems as an acceptor centre for the perovskite B-site. For reasons of local charge compensation, different kinds of defect associates invoking one and two oxygen vacancies are formed. These two kinds of extended defects differ in their electric and elastic properties. The results obtained are analyzed in order to characterize differences of the local structure in the Cu2+-defect center for morphotropic phase boundary compositions between the two systems. In particular, it is found that Cu2+-doping in KNN creates 50% more oxygen vacancies than the same amount of copper in PZT. Furthermore, local differences in covalent and ionic bonding are monitored.

Item Type: Article
Erschienen: 2009
Creators: Eichel, Rüdiger-A. and Erünal, Ebru and Drahus, Michael D. and Smyth, Donald M. and van Tol, Johan and Acker, Jérôme and Kungl, Hans and Hoffmann, Michael J.
Title: Local variations in defect polarization and covalent bonding in ferroelectric Cu2+-doped PZT and KNN functional ceramics at the morphotropic phase boundary
Language: English
Abstract:

Cu2+-doped Pb[Zr0.54Ti0.46]O3 (PZT) and Cu2+-doped [K0.5Na0.5]NbO3 (KNN) ferroelectrics with a dopant concentration of 0.25 mol% were investigated by means of multi-frequency and multi-pulse electron paramagnetic resonance (EPR) spectroscopy. Through the use of high magnetic fields and pulsed microwave fields an enhanced resolution was achieved yielding valuable information about the structural distortion at the dopant site. The results obtained suggest that Cu2+ substitutes for both systems as an acceptor centre for the perovskite B-site. For reasons of local charge compensation, different kinds of defect associates invoking one and two oxygen vacancies are formed. These two kinds of extended defects differ in their electric and elastic properties. The results obtained are analyzed in order to characterize differences of the local structure in the Cu2+-defect center for morphotropic phase boundary compositions between the two systems. In particular, it is found that Cu2+-doping in KNN creates 50% more oxygen vacancies than the same amount of copper in PZT. Furthermore, local differences in covalent and ionic bonding are monitored.

Journal or Publication Title: Physical Chemistry Chemical Physics
Volume: 11
Number: 39
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A2: Manufacturing and characterization of PZT-ceramics with defined defect chemistry
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
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
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
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 21 Jul 2011 08:43
Official URL: http://dx.doi.org/10.1039/b905642d
Additional Information:

SFB 595 Cooperation A2, B1

Identification Number: doi:10.1039/b905642d
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