RIKEN Center for Emergent Matter Science (CEMS) , Wako 351-0198, Japan.
Nano Lett. 2014 Jan 8;14(1):239-43. doi: 10.1021/nl403828u. Epub 2013 Dec 12.
The switching of electric polarization induced by electric fields, a fundamental functionality of ferroelectrics, is closely associated with the motions of the domain walls that separate regions with distinct polarization directions. Therefore, understanding domain-walls dynamics is of essential importance for advancing ferroelectric applications. In this Letter, we show that the topology of the multidomain structure can have an intrinsic impact on the degree of switchable polarization. Using a combination of polarization hysteresis measurements and piezoresponse force microscopy on a uniaxial organic ferroelectric, α-6,6'-dimethyl-2,2'-bipyridinium chloranilate, we found that the head-to-head (or tail-to-tail) charged domain walls are strongly pinned and thus impede the switching process; in contrast, if the charged domain walls are replaced with electrically neutral antiparallel domain walls, bulk polarization switching is achieved. Our findings suggest that manipulation of the multidomain topology can potentially control the switchable polarization.
电场诱导的电极化反转是铁电体的基本功能，它与分离具有不同极化方向区域的畴壁运动密切相关。因此，了解畴壁动力学对于推进铁电应用至关重要。在这封信件中，我们表明多畴结构的拓扑结构可能对可切换极化的程度产生内在影响。我们使用单轴有机铁电体 α-6,6'-二甲基-2,2'-联吡啶氯草酸盐的极化滞后测量和压电力显微镜相结合的方法，发现头对头（或尾对尾）带电畴壁被强烈钉扎，从而阻碍了开关过程；相比之下，如果用不带电的反平行畴壁取代带电畴壁，则可以实现体相极化反转。我们的发现表明，多畴拓扑结构的操纵有可能控制可切换极化。
