Dynamic scaling of ultrasonic damping near the nematic-smectic-A transition of TBBA

Citation
P. Sonntag et al., Dynamic scaling of ultrasonic damping near the nematic-smectic-A transition of TBBA, PHYS REV L, 84(9), 2000, pp. 1950-1953
Citations number
15
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW LETTERS
ISSN journal
00319007 → ACNP
Volume
84
Issue
9
Year of publication
2000
Pages
1950 - 1953
Database
ISI
SICI code
0031-9007(20000228)84:9<1950:DSOUDN>2.0.ZU;2-4
Abstract
We report a detailed study of the ultrasonic damping near the nematic-smect ic-A phase transition of terephtal-bis-p-p'-butylaniline (TBBA). Two mechan isms contribute to the damping. One is isotropic: it is associated with the critical fluctuations, and leads to a scaling behavior of the 3D-XY type w hich is observed up to 15 degrees C from the transition, even though the tr ansition is first order. The other is anisotropic: it appears only in the s mectic-A phase, and is associated with the relaxation of the order-paramete r modulus.