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Hardening of electromechanical properties in piezoceramics using a composite approach

Lalitha, K. V. and Riemer, Lukas M. and Koruza, Jurij and Rödel, Jürgen (2017):
Hardening of electromechanical properties in piezoceramics using a composite approach.
In: Applied Physics Letters, AIP Publishing, pp. 1-5, 111, (022905), ISSN 00036951, DOI: 10.1063/1.4986911, [Online-Edition: http://dx.doi.org/10.1063/1.4986911],
[Article]

Abstract

Piezoelectric applications such as ultrasonic motors, transformers and therapeutic ultrasonics demand high power generation with low losses, which is facilitated by “hard” ferroelectrics.Hardening of piezoelectric properties, characterized by high mechanical quality factor (Qm), is usually achieved by doping with lower valence elements, thereby tailoring the domain wall dynamics. In the present study, we demonstrate a hardening mechanism by developing composites of 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3 (NBT-6BT) with ZnO inclusions, as an alternative to chemical modifications. A decrease in the saturation polarization and total strain, higher internal bias fields, lower hysteretic losses and a two-fold increase in Qm are observed in comparison to NBT-6BT. The composite with 0.1 mole ratio of ZnO exhibits the highest Qm of 320 with d33=125 pC/N and Kp=0.29. A one-to-one correspondence between the increase in Qm and the decrease in the domain wall mobility is established from the ac field dependence of permittivity, in the framework of the Rayleigh law. A further increase in ZnO content beyond a mole ratio of 0.1 reduces Qm, but retains it at a higher level, as compared to NBT-6BT. The results are explained based on the poling-induced strain incompatibility between the matrix and the hard ZnO phase. This composite approach is therefore considered a generic hardening concept and can be extended to other ferroelectric systems. Published by AIP Publishing.

Item Type: Article
Erschienen: 2017
Creators: Lalitha, K. V. and Riemer, Lukas M. and Koruza, Jurij and Rödel, Jürgen
Title: Hardening of electromechanical properties in piezoceramics using a composite approach
Language: English
Abstract:

Piezoelectric applications such as ultrasonic motors, transformers and therapeutic ultrasonics demand high power generation with low losses, which is facilitated by “hard” ferroelectrics.Hardening of piezoelectric properties, characterized by high mechanical quality factor (Qm), is usually achieved by doping with lower valence elements, thereby tailoring the domain wall dynamics. In the present study, we demonstrate a hardening mechanism by developing composites of 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO3 (NBT-6BT) with ZnO inclusions, as an alternative to chemical modifications. A decrease in the saturation polarization and total strain, higher internal bias fields, lower hysteretic losses and a two-fold increase in Qm are observed in comparison to NBT-6BT. The composite with 0.1 mole ratio of ZnO exhibits the highest Qm of 320 with d33=125 pC/N and Kp=0.29. A one-to-one correspondence between the increase in Qm and the decrease in the domain wall mobility is established from the ac field dependence of permittivity, in the framework of the Rayleigh law. A further increase in ZnO content beyond a mole ratio of 0.1 reduces Qm, but retains it at a higher level, as compared to NBT-6BT. The results are explained based on the poling-induced strain incompatibility between the matrix and the hard ZnO phase. This composite approach is therefore considered a generic hardening concept and can be extended to other ferroelectric systems. Published by AIP Publishing.

Journal or Publication Title: Applied Physics Letters
Volume: 111
Number: 022905
Publisher: AIP Publishing
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
Date Deposited: 14 Jul 2017 11:19
DOI: 10.1063/1.4986911
Official URL: http://dx.doi.org/10.1063/1.4986911
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