Study of the temperature dependence of the giant electric field-induced strain in Nb-doped BNT-BT-BKT piezoceramics

Study of the temperature dependence of the giant electric field-induced strain in Nb-doped BNT-BT-BKT piezoceramics

Room-temperature (a) giant strain (b) polarisation in Nb-doped BNKBT ceramics [Display omitted] •Nb-doping of BNT-BKT-BT ceramics leads to giant electric field induced strain.•Temperature stability of the strain for Nb-doping of BNT-BKT-BT ceramics is field dependent.•2mol% Nb-doping is sufficient t...

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Bibliographic Details
Published in:Materials research bulletin Vol. 97; pp. 385 - 392
Main Authors: Obilor, Uchechukwu, Pascual-Gonzalez, Cristina, Murakami, Shunsuke, Reaney, Ian M., Feteira, Antonio
Format: Journal Article
Language:English
Published: Elsevier Ltd 01-01-2018
Subjects:
Ergodic
Giant strain
Non-ergodic
Pb-free piezoelectrics
Temperature stable
Non-ergodic
Giant strain
Temperature stable
Ergodic
Pb-free piezoelectrics
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Summary:Room-temperature (a) giant strain (b) polarisation in Nb-doped BNKBT ceramics [Display omitted] •Nb-doping of BNT-BKT-BT ceramics leads to giant electric field induced strain.•Temperature stability of the strain for Nb-doping of BNT-BKT-BT ceramics is field dependent.•2mol% Nb-doping is sufficient to drop the relaxor-to-ferroelectric transition below temperature. Dense Bi0.487Na0.427K0.06Ba0.026TiO3 (BNKBT) and Nb-doped Bi0.487Na0.427K0.06Ba0.026Ti0.98Nb0.02O3 (Nb-BNKBT) ceramics were prepared by the solid state reaction route. BNKBT is a non-ergodic relaxor and exhibits a piezoelectric response typical for a ferroelectric, whereas Nb-BNKBT is an ergodic relaxor and exhibits an electromechanical response typical for an incipient ferroelectric. The incorporation of 2 mol% of Nb into the BNKBT lattice is accompanied by an enhancement of the room-temperature unipolar field-induced strain from 0.19% to 0.43% at 75kV/cm. BNKBT shows a depolarisation temperature of ∼90°C, above which an electrostrictive response is observed, whereas Nb-BNKBT shows an electrostrictive response in the entire temperature range studied. At 40kV/cm, Nb-BNKBT exhibits a temperature stable electromechanical response in comparison with undoped BNKBT, but it worsens under higher electric fields. These results may motivate further investigations on the impact of minor doping and driving electric fields on the electromechanical response of Bi0.5Na0.5TiO3–Bi0.5K0.5TiO3–BaTiO3-based ceramics.
ISSN:0025-5408
1873-4227
DOI:10.1016/j.materresbull.2017.09.032