Origin of the large strain response in (K{sub 0.5}Na{sub 0.5})NbO{sub 3}-modified (Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-BaTiO{sub 3} lead-free piezoceramics

Journal Article · Fri May 01 04:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3121203· OSTI ID:21356145

Jo, Wook; Granzow, Torsten; Aulbach, Emil; Roedel, Juergen ^[1]; Damjanovic, Dragan ^[2]

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1. Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)
2. Ceramics Laboratory, EPFL, Lausanne CH-1015 (Switzerland)

The mechanism of the giant unipolar strain recently observed in a lead-free piezoceramic, 0.92(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.06BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3}[S.-T. Zhang, A. B. Kounga, E. Aulbach, H. Ehrenberg, and J. Roedel, Appl. Phys. Lett. 91, 112906 (2007) was investigated. The validity of the previously proposed mechanism that the high strain comes both from a significant volume change during the field-induced phase transition, from an antiferroelectric to a ferroelectric phase and the domain contribution from the induced ferroelectric phase was examined. Monitoring the volume changes from the simultaneously measured longitudinal and transverse strains on disk-shaped samples showed that the phase transition in this specific material does not involve any notable volume change, which indicates that there is little contribution from a volume change due to the phase transition to the total strain response. Temperature dependent hysteresis measurements on unpoled samples of a nearby ferroelectric composition, 0.93(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.06BaTiO{sub 3}-0.01(K{sub 0.5}Na{sub 0.5})NbO{sub 3} demonstrated that the origin of the large strain is due to the presence of a nonpolar phase that brings the system back to its unpoled state once the applied electric field is removed, which leads to a large unipolar strain.

• OSTI ID: 21356145
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BISMUTH COMPOUNDS
CHALCOGENIDES
DIELECTRIC MATERIALS
ELECTRIC FIELDS
FERROELECTRIC MATERIALS
HYSTERESIS
MATERIALS
NIOBATES
NIOBIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
POTASSIUM COMPOUNDS
REFRACTORY METAL COMPOUNDS
SODIUM COMPOUNDS
TEMPERATURE DEPENDENCE
TITANATES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS