Electric field-induced changes in the ferroelastic behavior of (Na1/2Bi1/2)TiO3-BaTiO3
Electric field-induced changes in the ferroelastic behavior of (Na1/2Bi1/2)TiO3-BaTiO3
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DOI：
10.1016/j.jeurceramsoc.2018.06.017
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发表时间：
2018-11-01
影响因子：
5.7
通讯作者：
Webber, Kyle G.
中科院分区：
文献类型：
--
作者：
Martin, Alexander;Khansur, Neamul H.;Webber, Kyle G.
在这项研究中，对跨同形相界（MPB）的极化和非极化多晶（1-x）（Na1/2Bi1/2）TiO3-xBaTiO（3）（NBT-xBT）的宏观机械行为进行了表征。由于场诱导的铁电相变，MPB (x = 6-7 mol%) 附近的 NBT-xBT 组合物显示出电极化样品的矫顽应力显着降低。机械行为的明显差异被认为是由于极化样品中不可逆电场引起的长程铁电有序转变所致。结果表明，弛豫-铁电转变和铁弹性畴壁运动的临界应力存在显着差异，这对无铅铁电材料的应用产生重要影响。为了进一步说明这一点，开发了一种在室温下电去极 NBT-xBT 的方法，从而产生具有长程铁电有序的未极化 NBT-xBT 材料。机械测试显示，尽管缺乏压电响应，但极化样品具有类似的宏观铁弹性行为。
In this study, the macroscopic mechanical behavior was characterized for poled and unpoled polycrystalline (1-x)(Na1/2Bi1/2)TiO3-xBaTiO(3) (NBT-xBT) for compositions across the morphotropic phase boundary (MPB). Due to a field-induced ferroelectric phase transformation, NBT-xBT compositions near the MPB (x = 6-7 mol%) showed a significant decrease in the coercive stress for electrically poled samples. The apparent difference in mechanical behavior is suggested to be due to an irreversible electric-field-induced transformation to long-range ferroelectric order in the poled samples. The results indicate a significant difference in the critical stresses for the relaxor-ferroelectric transition and ferroelastic domain wall motion, which can have important effects on applications for lead-free ferroelectrics. To further illustrate this, a method was developed to electrically depole NBT-xBT at room temperature, resulting in an unpoled NBT-xBT material with long-range ferroelectric order. Mechanical testing revealed analogous macroscopic ferroelastic behavior to the poled samples, despite the lack of a piezoelectric response.