The Magnetic-Field-Induced Birefringence of the Mixtures of the Chiral Molecules and the Ferronematic Liquid Crystals
The Magnetic-Field-Induced Birefringence of the Mixtures of the Chiral Molecules and the Ferronematic Liquid Crystals
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DOI：
10.1080/15421408708084229
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发表时间：
1987
影响因子：
0.7
通讯作者：
Shu-hsia Chen;S. Chiang
中科院分区：
文献类型：
--
作者：
Shu-hsia Chen;S. Chiang
Brochard和de Gennes在理论上描述的铁磁态可以通过在液晶中掺杂各向异性铁磁粒子来实现。成功地制备了低浓度手性分子掺杂铁电液晶的垂面液晶薄膜。从理论和实验两方面研究了分子取向引起的磁场诱导双折射。在低场区（<2.5G），理论上预测了垂直入射的探测光束的寻常光和非常光之间的感应相位差与外磁场的平方和样品膜厚度的五次方成正比。实验结果验证了这一点。手性分子的影响表现在有效弹性常数ke上，它随手性分子浓度的增加先减小后增大。
Abstract The ferronemtaic state which was described theoretically by Brochard and de Gennes can be achieved by doping the liquid crystal with anisotropic ferromagnetic particles. The homeotropic liquid crystal film was successfully prepared for the ferronematic liquid crystal doped with low concentration chiral molecules. The magnetic-field-induced-birefringence due to molecular reorientation was treated both theoretically and experimentally. In the low field regime (<2.5G), it is theoretically predicted that the induced phase difference between the ordinary and extraordinary ray of a normally incident probe beam is proportional to the square of the external magnetic field and to the fifth power of the thickness of the sample film. This is verified by the experimental results. The effect of the chiral molecules appears in the effective elastic constant, ke , which will decrease and then increase with respect to the increasing of the concentration of the chiral molecules.