Domain wall saddle point morphology in ferroelectric triglycine sulfate
Domain wall saddle point morphology in ferroelectric triglycine sulfate
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DOI：
10.1063/5.0152518
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发表时间：
2023-05-29
影响因子：
4
通讯作者：
Gregg, J. M.
中科院分区：
文献类型：
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作者：
McCluskey, C. J.;Kumar, A.;Gregg, J. M.
在极化上有发散的铁电磁畴壁通常具有相对于块体的增强的电导率。然而，在锗铅中，头对头和尾对尾的墙是电绝缘的。最近的研究表明，这是因为，当相反取向的结构域相遇时，通过结构域分叉和可疑的局部偶极旋转的组合来避免极发散。为了探索这种微结构的独特性或其他方面，我们使用层析压电响应力显微镜来绘制另一种单轴铁电系统的三维磁区形态：硫酸甘氨酸。这一映射揭示了大量的磁区壁鞍点，这是连锁分叉磁区的特征。在鞍点附近进行的导电原子力显微镜没有显示高度局部化的导电磁区壁截面的证据，在这些截面上可能暗示着极化的发散；这支持了发生局域偶极旋转以最大限度地减少任何潜在的极不连续的概念。总体而言，我们的研究证实了相互磁畴分叉和疑似局域偶极旋转并不是锗酸铅所特有的，相反，它可能广泛存在于其他单轴铁电材料中。
Ferroelectric domain walls, across which there is a divergence in polarization, usually have enhanced electrical conductivity relative to bulk. However, in lead germanate, head-to-head and tail-to-tail walls are electrically insulating. Recent studies have shown that this is because, when oppositely oriented domains meet, polar divergence is obviated by a combination of domain bifurcation and suspected local dipolar rotation. To explore the uniqueness, or otherwise, of this microstructure, we have used tomographic piezoresponse force microscopy to map three-dimensional domain morphologies in another uniaxial ferroelectric system: triglycine sulfate. This mapping reveals an abundance of domain wall saddle points, which are characteristic of interlocking bifurcated domains. Conducting atomic force microscopy, performed close to the saddle points, showed no evidence for highly localized conducting domain wall sections, across which a divergence in polarization might be implied; this supports the notion that localized dipolar rotation occurs to minimize any potential polar discontinuity. Overall, our study, therefore, confirms that mutual domain bifurcation and suspected local dipolar rotation are not unique to lead germanate and instead may be widely present in other uniaxial ferroelectrics.