Acoustic Parameters of Smectic B

Abstract
The temperature dependencies of velocity and attenuation coefficient of longitudinal ultrasound at frequency 3 – 27 MHz were obtained. The measurements were carried out for different orientation of wave vector and premary orientation of smectic normals. Experimental results are compared with theoretical predictions. It is shown that ultrasound velocity is increased at temperature phase transition to smectic B. The inverse sign of ultrasound velocity anisotropy is observed at phase transition smectic C – smectic B.

Keywords: smectic, ultrasound velocity, attenuation coefficient, phase transitions, anisotropy, elastic module, viscosity coefficient, relaxation, dispersion