Temperature‐Insensitive High Strain in Lead‐Free Bi0.5(Na0.84K0.16)0.5TiO3–0.04SrTiO3 Ceramics for Actuator Applications |
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| Authors: | Rizwan Ahmed Malik Ali Hussain Adnan Maqbool Arif Zaman Chang‐Won Ahn Jamil Ur Rahman Tae‐Kwon Song Won‐Jeong Kim Myong‐Ho Kim |
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| Affiliation: | 1. School of Advanced Materials Engineering, Changwon National University, Gyeongnam, Korea;2. Department of Physics, Abdul Wali Khan University, Mardan, KPK, Pakistan;3. Department of Physics, University of Ulsan, Ulsan, Korea;4. Department of Physics, Changwon National University, Gyeongnam, Korea |
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| Abstract: | Lead‐free piezoelectric ceramics, 0.96{Bi0.5 (Na0.84K0.16)0.5}1?xLix(Ti1?yNby)O3]–0.04SrTiO3 (BNKLiTN–ST) with x, y = 0–0.030, were synthesized by solid‐state reaction method. X‐ray diffraction patterns indicated that Li and Nb successfully diffused into the BNKT–ST lattice and formed a pure perovskite structure with x, y ≤ 0.025. Increasing the Li and Nb contents (x, y = 0.020) induced a phase transformation from the coexistent rhombohedral–tetragonal phases for pure BNKT–ST ceramics to a pseudocubic phase, resulting in degradation of the remnant polarization and coercive field. However, the field‐induced strain was markedly enhanced at x, y = 0.020, giving rise to a giant dynamic piezoelectric constant (d33* = Smax/Emax = 800 pm/V). Furthermore, the temperature dependence of the field‐induced strain response showed temperature‐insensitivity up to 120°C. To explore its potential for device applications, a 10‐layered stack‐type multilayer actuator was fabricated from the optimal composition (x, y = 0.020). This actuator showed a large Smax/Emax of 600 pm/V at a relatively low driving field of 4.5 kV/mm suggesting highly promising results in lead‐free BNT‐based ceramics. |
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