Temperature dependence of the dielectric characteristics of a 5CB liquid crystal within the relaxation region

The temperature dependence of the real part of the permittivity of a 4- n -pentyl-4-cyanobiphenyl liquid crystal was studied within a broad frequency range of 30–5000 MHz and in the temperature interval 20–60°C in the vicinity of the nematic-isotropic-liquid phase transition. It was established that the dispersion of the longitudinal component of the permittivity can be fitted well by a sum of two Debye terms with strongly differing relaxation times. The temperature and frequency dependence of the shorter relaxation time was determined for which the best fit between calculations and experiment was achieved.