Dynamic scaling of ultrasonic damping near the nematic-smectic- A transition of TBBA
We report a detailed study of the ultrasonic damping near the nematic-smectic- A phase transition of terephtal-bis- p-p(')-butylaniline (TBBA). Two mechanisms 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 which is observed up to 15 degrees C from the transition, even though the transition is first order. The other is anisotropic; it appears only in the smectic- A phase, and is associated with the relaxation of the order-parameter modulus.
Sonntag
P
Laboratoire de Dynamique des Fluides Complexes, Unite Mixte de Recherche C.N.R.S.-U.L.P. No. 7506, Universite Louis Pasteur, 4, rue Blaise Pascal, 67070 Strasbourg Cedex, France.
Collin
D
Martinoty
P