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Low electric field-driven giant strain response in 〈001〉 textured BNT-based lead-free piezoelectric materials

Bai, Wangfeng, Chen, Daqin, Zheng, Peng, Zhang, Jingji, Shen, Bo, Zhai, Jiwei, Ji, Zhenguo
Journal of materials science 2017 v.52 no.6 pp. 3169-3178
ambient temperature, ceramics, electric field, hysteresis, microstructure
The applied electric field to drive intended large strain response in Bi₀.₅Na₀.₅TiO₃-based piezoelectric ceramics is usually high (mostly with E ≥ 60 kV/cm) and remains a long-standing drawback for actual actuator applications. In this work, we report 〈001〉 oriented (1−x) (0.83Bi₀.₅Na₀.₅TiO₃–0.17Bi₀.₅K₀.₅TiO₃)–xBaTiO₃ (BNT–BKT–BT) lead-free piezoelectric ceramics using BT as the template particles to tailor the strain behavior under a low driving field. The strain response exhibited an increasing trend with the increasing grain orientation, and remarkably giant S ₘₐₓ/E ₘₐₓ of 800 pm/V was acquired under a relatively low electric field of 45 kV/cm in the optimized microstructure for textured BNT-BKT–1BT ceramics compared with the reported lead-free Bi-based perovskite ceramics. Furthermore, the achieved textured ceramics showed prominent electric field- and temperature-dependent strain characteristic featured by both a high room-temperature S ₘₐₓ/E ₘₐₓ of 621 pm/V under a very low driving field of 35 kV/cm and an achievable large S ₘₐₓ/E ₘₐₓ of 531 pm/V with almost vanished hysteretic behavior at high temperature. Our work may be helpful for designing BNT-based lead-free materials with promising strain response and thus provides a new approach to resolve this drawback of BNT-based lead-free piezoelectric ceramics.