FIELD-INDUCED PHASE-TRANSITIONS IN ANTIFERROELECTRIC LIQUID-CRYSTAL

Cell thickness dependence and field impression rate dependence of field-induced phase transition in an antiferroelectric liquid crystal (MHPOBC) have been investigated by observing the optical transmittance hysteresis loop and texture of the cells. In thin cells, pseudo-triple hysteresis loops due to coexistence of ferroelectric and antiferroelectric domains have been observed. In thick cells, an antiferroelectric phase is stabilized near the zero-field region of a ferrielectric phase of a field-temperature phase diagram. A possible model for molecular orientational structure of the phases and field-induced transitions among them is discussed on the basis of these experimental results.