The isotropic-nematic phase transition is generally a first-order phase transition. When an electric field is applied to a nematic liquid crystal with negative dielectric anisotropy, a tricritical point is theoretically predicted to appear on the temperature-electric field phase diagram. We have shown that soft mode can be observed by performing dielectric measurement under a DC electric field. In this study, we attempted to measure soft mode in nematic liquid crystal with negative dielectric anisotropy by the method proposed in our previous study. We found that a peak appears in the temperature dependence of the dielectric constant . Furthermore, we observed a Debye-type dielectric dispersion, which is considered to be contributed by the soft mode.
