Dielectric measurement for 1MC1EPOPB and 1BC1EPOPB ferroelectric liquid crystals of large spontaneous polarization

Dielectric measurements have been carried out using impedance analyzer for two ferroelectric liquid crystals R-4'(1-methoxycarbonyl-1-ethoxy) phenyl 4-(4 octyloxy phenyl) benzoate (1MC1EPOPB) and R-4'(1 butoxycarbonyl-1-ethoxy) phenyl 4-(4-octyloxy phenyl) benzoate (1BC1EPOPB). The two samples have large spontaneous polarization, +170 nC/cm/sup 2/ for 1MC1EPOPB and +240 nC/cm/sup 2/ for 1BC1EPOPB. The permittivity and dielectric loss have been measured at different temperatures in the range 70.0/spl deg/C to 110.0/spl deg/C for 1MC1EPOPB and 45.0/spl deg/C to 80.0/spl deg/C for 1BC1EPOPB in the frequency range 2 Hz to 2 MHz. Both of the ferroelectric liquid crystals, 1MC1EPOPB and 1BC1EPOPB show a new phase smectic X along with smectic C* and smectic A phases. The work reported in this paper is new and is very useful in understanding their application in switching devices.