Static and dynamic polar nanoregions in relaxor ferroelectric Ba(Ti1-xSnx)O3 system at high temperature
Static and dynamic polar nanoregions in relaxor ferroelectric Ba(Ti1-xSnx)O3 system at high temperature
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DOI：
10.1103/physrevb.85.014118
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发表时间：
2012-01-30
影响因子：
3.7
通讯作者：
Zhu, J.
中科院分区：
文献类型：
--
作者：
Xie, L.;Li, Y. L.;Zhu, J.
弛豫铁电体是在其最大介电常数温度下表现出介电色散而没有宏观相变到铁电态的材料。它们的特殊性能在各种介电和压电应用中得到了利用。由于人们普遍认为极性纳米区在弛豫量行为中起着至关重要的作用，因此研究原子结构如何影响弛豫量的性质引起了人们的极大兴趣。本文利用暗场成像和原子分辨率电子显微镜，研究了无铅铁电弛豫剂Ba(Ti1-xSnx)O-3体系在高温下的纳米和原子结构。测量了局部原子位移及其空间相关性，报道了弛豫剂中静态极性纳米区的原子结构。对于表现出正常铁电性的材料，则看不到这种静态极性结构。根据我们的实验观察，我们认为静态极性纳米区是导致无铅体系弛豫行为的原因。
Relaxor ferroelectrics are materials exhibiting dielectric dispersions in their maximum permittivity temperature without macroscopic phase transition into a ferroelectric state. Their exceptional properties are exploited in a variety of dielectric and piezoelectric applications. As it is generally believed that polar nanoregions play a crucial role in relaxor behavior, there are great interests in exploring how the atomic structures affect the relaxor properties. Here, using the dark field imaging and atomic-resolution electron microscopy, we investigate the nano and atomic structure of a lead-free ferroelectric-relaxor Ba(Ti1-xSnx)O-3 system at high temperature. The local atom displacements and their spatial correlations are measured, and the atomic structure of static polar nanoregions in the relaxors is reported. For the materials exhibiting normal ferroelectricity, no such static polar structures can be seen. Based on our experimental observations, we suggest the static polar nanoregions are responsible for the relaxor behavior in this lead-free system.