Dielectric Dispersion in the Antiferroelectric Liquid Crystal MHPOBC

Abstract
The dielectric dispersion in the ferroelectric and antiferroelectric phases of a smectic liquid crystal, 4-(1-methylheptyl-oxycarbonyl)phenyl 4'-octyloxybiphenyl-4-carboxylate (MHPOBC), has been measured with several frequencies between 100 Hz and 100 kHz. The soft mode with the Debye-type dispersion was observed in the phase transition from the Sm A phase to the ferroelectric Sm C* phase. In the Sm C* phase, the Goldstone mode was observed at the frequency of about 4.5 kHz. The dielectric dispersion in the Sm CA *, Sm Cα * and Sm Cγ * phases is discussed.