从宏观和纳米角度探索多晶铁电薄膜的极化重定向,Journal of Alloys and Compounds

在这项工作中，结合宏观和纳米分析，我们探索了畴结构和相对畴电场取向在多晶铁电薄膜极化重新取向过程中的作用。考虑到域结构的详细表征，通过压电响应力显微镜 (PFM) 执行宏观铁电和介电测量的结果进行解释。利用现象学模型获得与极化重定向、畴结构和畴壁迁移率相关的宏观参数。我们研究了四方Pb ( Zr , Ti ) O 3(PZT) 薄膜具有优先面内偏振（[100] 方向）和混合面内和面外偏振（[100] 和〈110〉方向）。结果揭示了薄膜的类似域结构，由高密度条纹域组成，宽度为 10 – 15 nm，由 90 ∘壁隔开。随着电场的施加，这种结构被重新排列，但在去除电场后仍保持了90∘壁的高密度。结合宏观和纳米分析，我们发现域的相对极化方向显着影响重新定向过程。对于[100]取向的膜，再取向主要发生由旋转一个-domains。对于这些电影，c域配置非常不稳定，导致在去除场后极化的高反向切换。另一方面，<110>薄膜取向的增加代表了具有偏振面外分量的域的增加，可以通过 180 ∘或 90 ∘切换和稳定重新定向。这导致更突然的重新定向过程和反向切换效应的减少。用现象学模型获得的参数与 PFM 观察到的响应非常一致，更好地解释了宏观测量。

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Exploring the polarization reorientation in polycrystalline ferroelectric thin films from the macroscopic and nanoscopic perspectives

In this work, combining macroscopic and nanoscopic analyses, we explored the role of domain structure and relative domain-electric field orientations in the polarization reorientation process in polycrystalline ferroelectric thin films. Results of macroscopic ferroelectric and dielectric measurements were interpreted considering a detailed characterization of the domain structure, performed by piezoresponse force microscopy (PFM). A phenomenological model was utilized to obtain macroscopic parameters related to the polarization reorientation, domain structure, and domain wall mobility. We investigated tetragonal Pb(Zr, Ti)O3 (PZT) thin films with preferential in-plane polarization ([100] direction) and mixed in-plane and out of plane polarization ([100] and 〈110〉 directions). Results revealed similar domain structures for the films, consisting of a high density of stripe domains, with a width of 10 – 15 nm, separated by 90∘ walls. With the application of an electric field, such a structure is rearranged but maintained a high density of 90∘ walls after removing the field. Combining the macroscopic and nanoscopic analyses, we found that the relative polarization orientation of the domains significantly impacts the reorientation process. For the [100] oriented film, the reorientation occurs mainly by the rotation of a-domains. For these films, the c-domain configuration is very unstable, resulting in a high backswitching of the polarization after removing the field. On the other side, the increase of the 〈110〉 film orientation represents an increase of domains with the out-of-plane component of polarization that can reorient by 180∘ or 90∘ switching and stabilize. This results in a more abrupt reorientation process and a reduction of the backswitching effect. The parameters obtained with the phenomenological model are in good agreement with the response observed by PFM and better explain the macroscopic measurements.