Dielectric properties in antiferroelectric liquid crystals and their DC bias effects

Abstract
Dielectric properties of TFMHPOBC, 3MC2PCPOPB and TFMHBOPP which indicate different phase sequences have been investigated as functions of temperature and dc bias field. In the antiferroelectric phase under no bias field, relaxations due to the soft mode and molecular rotation around the short axis are observed. The soft mode relaxation of TFMHBOPP does not decrease even in the transition from chiral smectic CA (Sm CA) phase to isotropic. Under dc bias field, a new relaxation is observed in the SmCA phase of TFMHPOBC and TFMHBOPP. The dielectric strength of this relaxation depends on the bias field, while the relaxation frequency is not affected by the dc bias field.