Anomalous Ultrasonic Absorption and Dispersion of Nematic Liquid Crystals near the Clearing Point

概要

論文の詳細を見る
The attenuation coefficient of longitudinal ultrasonic waves in the nematic-isotropic phase transition regions of liquid crystals has been measured as a function of both temperature and frequency. A sharp maximum is observed in the attenuation coefficient at the phase transition temperature T_c. The temperature dependence of the velocity has also been measured at 2 MHz, and a sharp minimum is observed at T_c. The anomalous changes of the ultrasonic propagation properties in the nematic phase near T_c are analysed and discussed by a phenomenological treatment based on the Landau-Khalatonikov theory of critical slowing down. On the other hand, behaviors in the isotropic phase near T_c are discussed in terms of the theory proposed recently by Imura and Okano. It is concluded that the anomalies are associated with the nematic-isotropic phase transition which is of first order even though it is nearly of second order.
社団法人応用物理学会の論文
1973-10-05