Phase structure, ferroelectric properties, and electric field-induced large strain in lead-free 0.99[(1∿span style='font-style: italic'>x)(Bi_0.5Na_0.5)TiO₃-x(Bi_0.5K_0.5)TiO₃]-0.01Ta piezoel

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• 作者：Na Chen¹ ; Wenjuan Yao¹ ; Cen Liang¹ ; Shanqu Xiao¹ ; Jigong Hao ; ^{haojigong@lcu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Zhijun Xu ; Ruiqing Chu
• 关键词：Lead-free ceramics ; Ferroelectricity ; Field-induced strain ; Phase transition
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：42
• 期：8
• 页码：9660-9666
• 全文大小：1782 K

文摘

Lead-free 0.99[(1−x)(Bi_0.5Na_0.5)TiO₃-x(Bi_0.5K_0.5)TiO₃]–0.01Ta piezoelectric ceramics were prepared by a conventional solid-state reaction process. The ferroelectric properties, and strain behaviors were characterized. Increase of the (Bi_0.5K_0.5)TiO₃ content induces a phase transition from coexistence of ferroelectric tetragonal and rhombohedral to a relaxor pseudocubic phase. Accordingly, the ferroelectric order is disrupted significantly with the increase of (Bi_0.5K_0.5)TiO₃ content and the destabilization of the ferroelectric order is accompanied by an enhancement of the unipolar strain, which peaks at a value of 0.35% (corresponding to a large signal d₃₃ of 438 pm/V) in samples with 20 mol% (Bi_0.5K_0.5)TiO₃ content. Temperature dependent measurements of both polarization and strain from room temperature to 120 °C suggested that the origin of the large strain is due to a reversible field-induced nonpolar pseudocubic-to-polar ferroelectric phase transformation.