Nonlinear Dielectric Spectroscopy of MHPOBC

Abstract

We apply nonlinear dielectric spectroscopy to an antiferroelectric liquid crystal MHPOBC at various smectic sub-phases. In the SmC_α* phase, the third-order nonlinear dielectric spectrum ϵ₃* is found to be composed of the contributions from ferroelectric soft mode and soft mode of the SmC_α* phase. The obtained spectrum is well ascribable by the theoretical one calculated by the Landau-type of phenomenological theory. In the SmC* phase, ϵ₃* shows a complicated form, and is different from one observed in usual ferroelectric liquid crystals. In the SmC_FI1*( SmC_γ*) phase, ferrielectric Goldstone mode with broad distribution of relaxation times is observed in both ϵ₁* and ϵ₃*.

Keywords:

• antiferroelectric liquid crystal
• MHPOBC
• nonlinear dielectric spectroscopy
• SmC*
• SmC_α*
• SmC_FI1*

Acknowledgments

This work is supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.