Observation of Unconventional Dynamics of Domain Walls in Uniaxial Ferroelectric Lead Germanate
Observation of Unconventional Dynamics of Domain Walls in Uniaxial Ferroelectric Lead Germanate
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DOI：
10.1002/adfm.202000284
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发表时间：
2020-03
影响因子：
19
通讯作者：
O. Bak;T. S. Holstad;Yueze Tan;Haidong Lu;D. Evans;K. Hunnestad;Bo Wang;J. McConville;P. Becker;L. Bohatý;I. Lukyanchuk;V. Vinokur;A. V. van Helvoort;J. Gregg;Long-qing Chen;D. Meier;A. Gruverman
中科院分区：
文献类型：
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作者：
O. Bak;T. S. Holstad;Yueze Tan;Haidong Lu;D. Evans;K. Hunnestad;Bo Wang;J. McConville;P. Becker;L. Bohatý;I. Lukyanchuk;V. Vinokur;A. V. van Helvoort;J. Gregg;Long-qing Chen;D. Meier;A. Gruverman
压电响应力显微镜（PFM）等扫描探针显微镜技术的应用为重新审视以前通过宏观电学测试方法研究的铁电体提供了可能性，并在其局部纳米级特性和整体响应之间建立了联系。报道了对铁电材料锗酸铅Pb 5Ge 3 O 11中畴结构的静态和动态行为的纳米级PFM研究和相场模拟。揭示了几个不寻常的现象：1）在顺电-铁电相变过程中畴的形成，表现出非典型的冷却速率依赖性; 2）与迄今观察到的典型畴生长行为相反，由于畴壁在垂直于极轴的方向上的优先运动，意外地电诱导扁畴的形成; 3）在180°头对头（H-H）和尾对尾（T-T）畴壁处不存在束缚电荷，由于极化不连续性，这些畴壁通常在其他铁电体中表现出显著的电荷密度。这种惊人的不同的行为是合理的相场模拟的动力学不带电的H-H和T-T畴壁。这些结果为铁电畴界的涌现物理学提供了新的见解，揭示了传统伊辛型壁所不具有的不寻常特性。
Application of scanning probe microscopy techniques such as piezoresponse force microscopy (PFM) opens the possibility to re‐visit the ferroelectrics previously studied by the macroscopic electrical testing methods and establish a link between their local nanoscale characteristics and integral response. The nanoscale PFM studies and phase field modeling of the static and dynamic behavior of the domain structure in the well‐known ferroelectric material lead germanate, Pb5Ge3O11, are reported. Several unusual phenomena are revealed: 1) domain formation during the paraelectric‐to‐ferroelectric phase transition, which exhibits an atypical cooling rate dependence; 2) unexpected electrically induced formation of the oblate domains due to the preferential domain walls motion in the directions perpendicular to the polar axis, contrary to the typical domain growth behavior observed so far; 3) absence of the bound charges at the 180° head‐to‐head (H–H) and tail‐totail (T–T) domain walls, which typically exhibit a significant charge density in other ferroelectrics due to the polarization discontinuity. This strikingly different behavior is rationalized by the phase field modeling of the dynamics of uncharged H–H and T–T domain walls. The results provide a new insight into the emergent physics of the ferroelectric domain boundaries, revealing unusual properties not exhibited by conventional Ising‐type walls.