SmC alpha* domains in SmC beta* phase of antiferroelectric liquid crystals

The ferrielectricity and domain structures of the chiral smectic C-beta pha se (SmCbeta*) in antiferroelectric liquid crystals were investigated. The r eal part of complex dielectric constant epsilon' in SmCbeta* shows two-step decrease with increasing DC bias field. Each decrease corresponds to the s uppression of relaxational two modes: one is the ferroelectric Goldstone mo de and the other is a new mode induced by DC bias field. The relaxational f requency of the latter mode is nearly the same as that of chiral smectic C- alpha phase (SmCalpha*). Another mode was observed at the field strength wh ere epsilon' shows steeply decrease. This mode may be attributed to the bou ndary motion between domains or phases. Three peaks of the switching curren t were observed in SmCbeta* and also in the lower-temperature region of SmC alpha*. The peak positions are continuously linked to those of SmCalpha*. I t can be said that the antiferroelectric ordering of SmCalpha* may appear a s domains even in SmCbeta* by electric bias field.