The Influence of Random Disorder on the Biquadratic and Piezoelectric Bilinear Coupling in a Ferroelectric Liquid Crystal

On the basis of the extended Landau mean field model for the SmA—SmC* phase transition the temperature dependence of the dielectric strength and of the characteristic relaxation frequency of the soft mode are analyzed and some parameters involved in the free energy expansion are determined. The analogies and differences between the influence of the aerosil density and a dc electric field are shown.

Keywords:

• Ferroelectric liquid crystal
• aerosil
• dielectric spectroscopy
• random disorder

Acknowledgments

This work has been supported by the Fund for Scientific Research Flanders, Belgium (FWO, project G.0246.02). S.A.R. acknowledges the receipt of a senior postdoctoral fellowship from the Research Council of K.U. Leuven.