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Characterization of the local layr structure in ferroelectricliquid crystals using synchrotron X-ray micro-diffraction

使用同步加速器 X 射线微衍射表征铁电液晶的局部层结构

基本信息

批准号：
07455016
负责人：
IIDA Atsuo
金额：
$ 3.07万
依托单位：
INSTITUTE OF MATERIALS STRUCTURE SCIENCE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

The local layr structure of the broad and narrow wall of a zig-zag defect in a thin-surface stabilized ferroelectric liquid crystal cell was characterized using a synchrotron X-ray microbeam ofless than 5 mum and 1mum spatial resolution. A high precision goniometer using an air bearing system was used. Since the width of the narrow wall is a few mum, the newlydeveloped high precision and high spatial resolution system was quite effective. By using a rocking curve measurement at the narrow wall, the direction of the layr normal depends on the position in the wall and the layr bends in both the w and c direction contrary to the previous plane layr model. The bent layr structure is realized due to the restriction of the constant layr spacing.The local layr structure response to the low electric field was measured at and around the broad wall. Multiple or broad peaks appeared in the rocking curveat the broad wall change into a single and sharp peak when the electricfield is applied to the cell. These observation suggests that the pseudo-bookshelf structure at the broad wall becomes the bookshelf structure with the higher layr perfection owing to the field induced torque on the layrs. The frequency dependence of the rockingcurve profileindicates the relaxation time of the local layr response to the electricfields. It was also observed that the layr imperfection in the S_C phase and S_A phase were related each other. It is concluded that the present method is quite effective to characterize the local layr structure of smectic liquid crystals.

本文用同步辐射X射线微束对薄表面稳定铁电液晶盒中锯齿形缺陷的宽壁和窄壁的局域层结构进行了表征，空间分辨率小于5 μ m，空间分辨率小于1 μ m。使用了使用空气轴承系统的高精度测角仪。由于窄壁的宽度只有几个微米，因此新开发的高精度和高空间分辨率系统是非常有效的。通过在窄壁处使用摇摆曲线测量，层法线的方向取决于在壁中的位置，并且层在w和c方向上弯曲，这与先前的平面层模型相反。在恒定层间距的限制下，实现了弯曲层结构，测量了宽壁处及宽壁周围的局部层结构对低电场的响应。当外加电场作用于细胞时，细胞的摇摆曲线出现多个或宽峰，宽壁处的摇摆曲线变为单个尖锐的摇摆曲线。这些观测结果表明，由于层间的场致扭矩，宽墙处的伪书架结构变成了层间完整度较高的书架结构。摇摆曲线的频率依赖性表明了局域层对电场响应的弛豫时间。还观察到S_C相和S_A相的层缺陷是相互关联的。结果表明，该方法对表征近晶相液晶的局域层结构是十分有效的。