论文标题
纳米级的单斜形对称性在无铅铁电bazr $ _ {x} $ ti $ _ {1-x} $ o $ $ _ {3} $ ceramics $ ceramics
Monoclinic symmetry at the nanoscale in lead-free ferroelectric BaZr$_{x}$Ti$_{1-x}$O$_{3}$ ceramics
论文作者
论文摘要
局部结构对称性在铁电材料的功能中起关键作用，并且通常发现与平均对称性不同。在这里，我们研究了PB无PB BAZR $ _ {X} $ ti $ _ {1-x} $ o $ $ $ _ {3} $（x $ \ leq $ 0.10）中的真实空间纳米级结构，这是通过配对分布功能测量值，由传输电子显微镜和X射线衍射。我们的观察结果表明存在菱形扭曲的单位细胞。但是，在中间长度尺度（至少高达5 nm）下，单斜层对称性的纳米级相关区域存在。观察到弯曲的沮丧纳米域的观察可以补充。此外，发现平均结构具有共存的单斜骨和菱形对称性。我们对两相铁电状态的观察与向掺杂的Batio $ _ {3} $报道的常规多态相边界的干扰性不稳定性形成对比。
Local structural symmetries play a key role in the functionalities of ferroelectric materials and are often found different from average symmetry. Here, we study the real space nanoscale structure in Pb-free BaZr$_{x}$Ti$_{1-x}$O$_{3}$ (x $\leq$ 0.10) by pair distribution function measurements, complemented by transmission electron microscopy and x-ray diffraction. Our observations show existence of the rhombohedrally distorted unit cells; however, at intermediate length scales, at least up to 5 nm, there exist nano-scale correlated regions of monoclinic symmetry. This is complemented by the observation of curved frustrated nanodomains. Further, the average structure is found to have coexisting monoclinic and rhombohedral symmetries. Our observation of a two-phase ferroelectric state is in contrast to interferroelectric instabilities of conventional polymorphic phase boundaries reported for doped BaTiO$_{3}$.
