Temperature‐Insensitive (K,Na)NbO3‐Based Lead‐Free Piezoactuator Ceramics |
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Authors: | Ke Wang Fang‐Zhou Yao Wook Jo Danka Gobeljic Vladimir V Shvartsman Doru C Lupascu Jing‐Feng Li Jürgen Rödel |
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Affiliation: | 1. State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China;2. Institute of Materials Science, Technische Universit?t Darmstadt, Darmstadt 64287, Germany;3. Institute for Materials Science, Universit?t Duisburg‐Essen, Essen 45141, Germany |
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Abstract: | The development of lead‐free piezoceramics has attracted great interest because of growing environmental concerns. A polymorphic phase transition (PPT) has been utilized in the past to tailor piezoelectric properties in lead‐free (K,Na)NbO3 (KNN)‐based materials accepting the drawback of large temperature sensitivity. Here a material concept is reported, which yields an average piezoelectric coefficientd33 of about 300 pC/N and a high level of unipolar strain up to 0.16% at room temperature. Most intriguingly, field‐induced strain varies less than 10% from room temperature to 175 °C. The temperature insensitivity of field‐induced strain is rationalized using an electrostrictive coupling to polarization amplitude while the temperature‐dependent piezoelectric coefficient is discussed using localized piezoresponse probed by piezoforce microscopy. This discovery opens a new development window for temperature‐insensitive piezoelectric actuators despite the presence of a polymorphic phase transition around room temperature. |
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Keywords: | lead‐free materials piezoceramics temperature‐insensitive materials strain |
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