Dielectric and electro-optical parameters of two ferroelectric liquid crystals: a comparative study

Abstract

Dielectric relaxation and an electro-optical study of two ferroelectric liquid crystals having different spontaneous polarizations (Felix 16/100 and Felix 17/000) showing SmC* and SmA phases have been performed in the temperature range 30–80 ∘C. The experimental data have been used to determine different relaxation parameters, viz. distribution parameter, relaxation frequency, dielectric strength and rotational viscosity. The Goldstone mode of dielectric permittivity has been well observed for both the samples under investigation. The activation energy of both the samples has also been determined by the best theoretical fitting of the Arrhenius plot. We have also evaluated the optical response time and anchoring energy coefficients from electro-optical measurement techniques for these samples.

Zinc Oxide (1% Cu) Nanoparticle in Nematic Liquid Crystal: Dielectric and Electro-Optical Study

“…The detailed method for preparation of sample cells with planar and homeotropic alignment is discussed in our earlier papers. [19][20][21] The empty sample cells were calibrated using analytical reagent (AR) grade CCl 4 and benzene as standard references for dielectric studies. The LC suspension was prepared by non-synthetic chemical method in the weight ratio 1 : 100 (i.e., 1% concentration of nanoparticles in nematic LC).…”

“…The temperature stability was better than AE0:1 C within the measurement. The data obtained at higher frequencies were strongly affected by the ITO relaxation, 20,21) therefore data at f > 10 MHz are omitted.…”

“…(1b) for high frequency effect due to the ITO resistance and lead inductance. 20,21) By the least square fitting of above equation into experimental data we have removed the low and high frequency errors.…”