The effect of Fe-acceptor doping on the electrical properties of Na1/2Bi1/2TiO3 and 0.94 (Na1/2Bi1/2)TiO3-0.06 BaTiO3
The effect of Fe-acceptor doping on the electrical properties of Na1/2Bi1/2TiO3 and 0.94 (Na1/2Bi1/2)TiO3-0.06 BaTiO3
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DOI：
10.1111/jace.16401
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发表时间：
2019-09-01
影响因子：
3.9
通讯作者：
Froemling, Till
中科院分区：
文献类型：
--
作者：
Steiner, Sebastian;Seo, In-Tae;Froemling, Till
Na1/2Bi1/2TiO3 (NBT) 基陶瓷是最有前途的无铅铁电材料之一。预计 NBT 的缺陷化学和掺杂效应将与铅基材料中观察到的类似，然而，受主掺杂不会导致铁电硬化。相反，会引起高氧离子电导率。然而，对于与铁电应用更相关的 BaTiO3 (BT) 固溶体，迄今为止尚未观察到如此剧烈的电性能变化。为了合理化 NBT 及其固溶体之间的缺陷化学差异，研究了具有不同铁掺杂浓度的 94(Na1/2Bi1/2TiO3)-0.06 BaTiO3 (NBT-6BT) 组合物。研究表明，这些材料表现出与 NBT 非常相似的行为，并且 NBT-6BT 也可以产生极高的氧离子电导率。 NBT-6BT 和 NBT 之间的主要区别在于离子电导率与掺杂剂浓度的依赖性范围。之前对 NBT-6BT 的研究尚未达到足够高的掺杂浓度来观察高电导率。因此，相同的缺陷化学模型可以应用于 NBT 及其固溶体。这将有助于合理化掺杂对 NBT 陶瓷铁电性能以及与退化和疲劳相关的缺陷化学的影响。
Na1/2Bi1/2TiO3 (NBT) based ceramics are amongst the most promising lead-free ferroelectric materials. It was expected that the defect chemistry and the effect of doping of NBT would be similar to that observed for lead based materials, however, acceptor doping does not lead to ferroelectric hardening. Instead, high oxygen ionic conductivity is induced. Nevertheless, for solid solutions with BaTiO3 (BT), which are more relevant with respect to ferroelectric applications, such a drastic change of electrical properties has not been observed so far. To rationalize the difference in defect chemistry between NBT and its solid solution 94(Na1/2Bi1/2TiO3)-0.06 BaTiO3 (NBT-6BT) compositions with different concentrations of Fe-dopant were investigated. The study illustrates that the materials exhibit very similar behavior to NBT, and extraordinarily high oxygen ionic conductivity could also be induced in NBT-6BT. The key difference between NBT-6BT and NBT is the range of the dependence of ionic conductivity with dopant concentration. Previous studies of NBT-6BT have not reached sufficiently high dopant concentrations to observe high conductivity. In consequence, the same defect chemical model can be applied to both NBT and its solid solutions. This will help to rationalize the effect of doping on ferroelectric properties of NBT-ceramics and defect chemistry related degradation and fatigue.