Department of Materials Science and Engineering, University of Michigan-Ann Arbor, Ann Arbor, Michigan 48109, USA.
Nat Commun. 2011 Dec 20;2:591. doi: 10.1038/ncomms1600.
Ferroelectric materials are characterized by a spontaneous polarization, which can be reoriented with an applied electric field. The switching between polarized domains is mediated by nanoscale defects. Understanding the role of defects in ferroelectric switching is critical for practical applications such as non-volatile memories. This is especially the case for ferroelectric nanostructures and thin films in which the entire switching volume is proximate to a defective surface. Here we report the nanoscale ferroelectric switching of a tetragonal PbZr(0.2)Ti(0.8)O(3) thin film under an applied electric field using in situ transmission electron microscopy. We found that the intrinsic electric fields formed at ferroelectric/electrode interfaces determine the nucleation sites and growth rates of ferroelectric domains and the orientation and mobility of domain walls, whereas dislocations exert a weak pinning force on domain wall motion.
铁电材料的特征是自发极化，可以通过外加电场重新定向。极化畴之间的转换由纳米级缺陷介导。理解缺陷在铁电开关中的作用对于实际应用至关重要，例如非易失性存储器。对于铁电纳米结构和薄膜尤其如此，在这些结构和薄膜中，整个开关体积接近有缺陷的表面。在这里，我们使用原位透射电子显微镜报告了在施加电场下四方 PbZr(0.2)Ti(0.8)O(3) 薄膜的纳米级铁电开关。我们发现，在铁电/电极界面形成的固有电场决定了铁电畴的成核位置和生长速率以及畴壁的取向和迁移率，而位错对畴壁运动施加较弱的钉扎力。
