Sharma P, Reece T, Wu D, Fridkin V M, Ducharme S, Gruverman A
Department of Physics and Astronomy, University of Nebraska Lincoln, Lincoln, NE 68588-0111, USA.
J Phys Condens Matter. 2009 Dec 2;21(48):485902. doi: 10.1088/0953-8984/21/48/485902. Epub 2009 Oct 30.
High-resolution studies of domain configurations in Langmuir-Blodgett films of ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), have been carried out by means of piezoresponse force microscopy (PFM). Changes in film thickness and morphology cause significant variations in polarization patterns. In continuous films and nanomesas with relatively low thickness/grain aspect ratio (<1/10), the relationship between the average domain size and thickness follows the Kittel law. Nanomesas with high aspect ratio (>1/5) exhibit significant deviations from this law, suggesting additional surface-energy-related mechanisms affecting the domain patterns. Polarization reversal within a single crystallite has been demonstrated and local switching parameters (coercive voltage and remnant piezoresponse) have been measured by monitoring the local hysteresis loops. Reliable control of polarization at the sub-grain level demonstrates a possibility of studying the mechanism of the intrinsic switching behavior down to the molecular scale.
利用压电响应力显微镜（PFM）对铁电聚合物聚偏二氟乙烯 - 三氟乙烯（P(VDF-TrFE)）的朗缪尔 - 布洛杰特薄膜中的畴结构进行了高分辨率研究。薄膜厚度和形态的变化会导致极化模式发生显著变化。在厚度/晶粒纵横比相对较低（<1/10）的连续薄膜和纳米台地中，平均畴尺寸与厚度之间的关系遵循基特尔定律。高纵横比（>1/5）的纳米台地表现出与该定律的显著偏差，这表明存在影响畴模式的与表面能相关的额外机制。已经证明了在单个微晶内的极化反转，并通过监测局部滞后回线测量了局部开关参数（矫顽电压和剩余压电响应）。在亚晶粒水平上对极化的可靠控制表明，有可能研究直至分子尺度的本征开关行为机制。
