Dielectric Biaxiality in SC Host Systems
Dielectric Biaxiality in SC Host Systems
复制标题
SC 主机系统中的介电双轴性
DOI：
10.1080/00268949108030939
复制
发表时间：
1991
影响因子：
0.7
通讯作者：
J. Sambles
中科院分区：
文献类型：
--
作者：
J. C. Jones;E. Raynes;M. Towler;J. Sambles
摘要AC场稳定的铁电SC* 液晶的人字形层的几何形状需要有一个显着的介电双轴性。1，2为了研究这一点，SC主机混合物的基础上的苯基嘧啶和表现出的N-SA-SC相序列的电介电常数的报告。在25°C时，介电各向异性发生大的弛豫，导致介电各向异性的符号反转，交叉频率为25 kHz。然后，使用消光角测量作为在对应于Δ ε> 0、Δe <0和δe < 0的频率下施加的电压的函数来表征宿主电光行为，并且使用具有双轴介电张量的倾斜层模型来解释结果。SC介电双轴性的大小，在平面均匀的几何形状和锥角的层倾斜角的确定。测量其他几个主机常用的商业FLC混合物的报告，它表明，在每种情况下，介电双轴性…
Abstract AC field stabilisation of ferroelectric SC* liquid crystals with the chevron layer geometry requires that there is a significant dielectric biaxiality.1,2 To investigate this, the electric permittivities of an SC host mixture based on the phenyl pyrimidines and exhibiting an N-SA-SC phase sequence are reported. A large relaxation of e∥ occurred, which caused a sign reversal of the dielectric anisotropy with a crossover frequency of 25 kHz at 25°C. The host electro-optic behaviour was then characterised using extinction angle measurements as a function of applied voltage at frequencies corresponding to Δ≈ > 0, Δe ≈ 0 and δe < 0, and the results explained using a tilted layer model with a biaxial dielectric tensor. The magnitude of the SC dielectric biaxiality, the layer tilt angle in the planar homogeneous geometry and the cone angle are determined. Measurements for several other hosts commonly used in commercial FLC mixtures are reported and it is shown that in each case the dielectric biaxiality...