Abstract
The ultrasonic velocity and attenuation of TA[100] acoustic waves have been measured as a function of temperature and frequency in CN mixed single crystals. Relaxation behavior is revealed by comparing our ultrasonic elastic stiffness data with hypersonic data obtained from Brillouin scattering. Combining ultrasonic velocity and attenuation data we are able to determine the Kramers-Kronig ratio R in the disordered paraelastic phase and to estimate it in the orientational glass phase. For the regime ω≪1, R is a direct measure of the cooperative quadrupolar clamped relaxation time , which can be represented by the empirical form ln=-T in the paraelastic phase. Quadrupolar relaxation processes in the orientational glass state are also discussed.
- Received 14 March 1991
DOI:https://doi.org/10.1103/PhysRevB.44.6731
©1991 American Physical Society