Nonlinear response of a ferroelectric liquid crystal

Abstract

We have measured the nonlinear dielectric susceptibilities, α₃,o' α₃ l and α₅,₀ of a ferroelectric liquid crystal in the paraelectric phase (SmA). The results were analyzed by using the Orihara and Ishibashi theory, which was derived from the time-dependent Ginzburg-Landau (TDGL) equation. The dispersions of the nonlinear susceptibilities and the Cole-Cole plots obtained from the experiment were well reproduced by the theory. The relaxation times obtained from the different nonlinear susceptibilities were almost the same with the one from the linear susceptibility, indicating that there should be only one relaxation time in the system even when the nonlinear phenomena are concerned. As a result we have shown that the TDGL equation is still valid in obtaining the nonlinear susceptibilities as well as the linear one.