Orientation‐Dependence of Thermal Depolarization and Phase Development in Bi1/2Na1/2TiO3‐BaTiO3 Single Crystals
Orientation‐Dependence of Thermal Depolarization and Phase Development in Bi1/2Na1/2TiO3‐BaTiO3 Single Crystals
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DOI：
10.1111/jace.13843
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发表时间：
2015-12
影响因子：
3.9
通讯作者：
D. Schneider;J. Rödel;D. Rytz;T. Granzow
中科院分区：
文献类型：
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作者：
D. Schneider;J. Rödel;D. Rytz;T. Granzow
研究了（1 − x）Bi 1/2Na 1/2 TiO 3 − xBaTiO 3（BNT − 100 xBT）的热释电性质的方向依赖性，使用了具有明确取向的单晶样品（x = 0.036和x = 0.063）。的铁电和介电滞后的随温度变化的测量结果进行了比较。发现每个晶体组合物的去极化温度Td取决于晶体取向，这一事实是由各自的域配置的稳定性的差异来解释的。一个合理化的观察，Td不同的铁电弛豫转变温度，取决于取向。BNT − 3.6BT的磁滞曲线是典型的具有铁电-弛豫转变的菱面体系统，接近Td的极化反转发生在多步过程中，包括铁电畴衰减为极性纳米区和畴的重新形成。BNT − 6.3BT，一种在准同型相界区域的成分，表现出相同的特征，但另外的特征是场诱导的菱面体和四面体对称之间的转变。这种组合导致d33*=1886 pm/V的有效压电系数。
The direction-dependence of pyroelectric properties of (1 − x)Bi1/2Na1/2TiO3 − xBaTiO3 (BNT − 100xBT) is investigated, using single crystal samples with well-defined orientations for x = 0.036 and x = 0.063. The results are compared with those of temperature-dependent measurements of the ferroelectric and dielectric hysteresis. The depolarization temperature Td of each crystal composition is found to depend on crystal orientation, a fact that is explained by differences in the stability of respective domain configurations. A rationalization is offered for the observation that Td differs from the ferroelectric-relaxor transition temperature, depending on orientation. The hysteresis curves of BNT − 3.6BT are typical for a rhombohedral system with a ferroelectric-relaxor transition, with polarization reversal close to Td occurring in a multistep process that includes decay of ferroelectric domains into polar nanoregions and re-formation of domains. BNT − 6.3BT, a composition in the region of the morphotropic phase boundary, shows the same feature, but additionally is characterized by a field-induced transition between rhombohedral and tetragonal symmetry. This combination results in an effective piezoelectric coefficient of d33*=1886 pm/V.