TEMPERATURE AND BIAS-FIELD DEPENDENCES OF DIELECTRIC BEHAVIOR IN THE ANTIFERROELECTRIC LIQUID-CRYSTAL, (R)-MHPOBC

Temperature and bias-field dependences of dielectric behaviour in the antiferroelectric liquid crystal, R-MHPOBC, were investigated (see als o previous paper). There are mainly two relaxation modes in the SmCalp ha and SmC* phases: one behaves as the soft-mode, which shows signifi cant slowing down in the SmA and SmCalpha* phases; the other one appe ars at lower frequencies and changes the dielectric strength remarkabl y, especially in the SmC phase, which is considered to relate to the azimuthal phase-fluctuation of molecules in the parallel tilt sequence s of the smectic layers. These two modes show different bias field dep endences in different C subphases. In the SmCA* phase, two other type s of relaxation mode were observed, which are probably due to the in-p hase and anti-phase azimuthal angle fluctuations of molecules in the a nti-tilt pairs.