Smectic-A*-smectic-C* transition in a ferroelectric liquid crystal without smectic layer shrinkage.
The smectic layer spacing of a nonfluorinated ferroelectric liquid crystal (FLC) compound with almost no shrinkage and only minor tendency to form zigzag defects was characterized by small angle x-ray diffraction. The material lacks a nematic phase. The smectic-A*-smectic-C* phase transition was studied by measuring the thermal and electric field response of the optical tilt and the electric polarization. These properties are described very well by a Landau expansion even without introduction of a higher-order Theta(6) term. This result suggests a pure second-order phase transition far from tricriticality and differs considerably from the typical behavior of the A*-C* transition in most FLC materials.
Giesselmann
F
F
Institute of Physical Chemistry, Clausthal University of Technology, Arnold-Sommerfeld-Strasse 4, D-38678 Clausthal-Zellerfeld, Germany.
Zugenmaier
P
P
Dierking
I
I
Lagerwall
S T
ST
Stebler
B
B
Kaspar
M
M
Hamplová
V
V
Glogarová
M
M