FIELD-INDUCED PHASE-TRANSITIONS IN ANTIFERROELECTRIC LIQUID-CRYSTAL

Cell thickness dependence and field impression rate dependence of fiel d-induced phase transition in an antiferroelectric liquid crystal (MHP OBC) have been investigated by observing the optical transmittance hys teresis loop and texture of the cells. In thin cells, pseudo-triple hy steresis loops due to coexistence of ferroelectric and antiferroelectr ic domains have been observed. In thick cells, an antiferroelectric ph ase is stabilized near the zero-field region of a ferrielectric phase of a field-temperature phase diagram. A possible model for molecular o rientational structure of the phases and field-induced transitions amo ng them is discussed on the basis of these experimental results.