Critical behavior of dielectric permittivity and nonlinear dielectric effect in the isotropic phase of nematogens

Abstract

The paper shows that the behavior of dielectric permittivity and its changes in a strong electric field can be described in the way analogous to that applied in critical binary solutions. Basing on measurement in 4,4-n-hexylcyanobiphenyl and 4,4-n-tetracyanobiphenyl (4CB) it was possible to portray the temperature behavior of dielectric permittivity and NDE from T<SUB>c</SUB> + 50 K. IN the case of 4CB the satisfied description was possible despite the fact that the sample crystallizes before reaching the clearing point. NDE tests was conducted for the measurement frequency f equals 70 kHz, what allowed to avoid the in fluence of relaxation processes on results.