Dielectric dispersion in a dual-frequency smectic A liquid crystal PPEP(3F6)-CN/P(CN)P6-6 mixture

This study examined the effects of temperature on the dielectric dispersion of cells holding a PPEP(3F6)-CN/P(CN)P6-6 mixture in the smectic A phase with homeotropic or homogeneous alignments, employing frequencies from 100 Hz to 1 MHz. The Cole-Cole function in conjunction with the DC conductivity was employed to assess these dispersion. In the mixture, it was observed that the dielectric anisotropy changed its sign depending on the frequency. This is the first observation of such a dual-frequency characteristic in the smectic phase to the best of our knowledge, although some dual-frequency nematic liquid crystals have been reported thus far. The value of the crossover frequency, fc, where the sign of the anisotropy was observed to change, was determined to be correlated with the relaxation frequency, fr, for the specimen.