Nematic biaxiality in a bent-core material.
Nematic biaxiality in a bent-core material.
复制标题
弯芯材料中的向列双轴性。
DOI：
10.1103/physreve.81.051706
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Satyendra Kumar
中科院分区：
文献类型：
--
作者：
H. Yoon;Shin;R. Y. Dong;A. Marini;K. A. Suresh;M. Srinivasarao;Satyendra Kumar
The results of a recent investigation of the nematic biaxiality in a bent-core mesogen (A131) are in apparent disagreement with earlier claims. Samples of mesogen A131 used in the two studies were investigated with polarized optical microscopy, conoscopy, carbon-13 NMR, and crossover frequency measurements. The results demonstrate that textural changes associated with the growth of biaxial nematic order appear at ∼149 °C. The Maltese cross observed in the conoscopic figure gradually splits into two isogyres at lower temperatures indicating phase biaxiality. Presence of the uniaxial to biaxial nematic phase transition is further confirmed by temperature trends of local order parameters based on 13C chemical shifts in NMR experiments. Frequency switching measurements also clearly reveal a transition at 149 °C. Differences between the two reports appear to be related to the presence of solvent, impurities, and/or adsorbed gases in samples of A131 used in the study of Van Le [Phys. Rev. E 79, 030701 (2009)].
