Threshold properties of nanodoped surface stabilized ferroelectric liquid crystals under electric and magnetic fields

Abstract

Surface stabilized ferroelectric liquid crystal (SSFLC) doped with ferroelectric nanoparticles shows interesting polarization and orientational behavior in external fields. In this work we study the behavior of a nanodoped SSFLC subjected simultaneously to electric and magnetic fields. The threshold fields and maximum deviation of the polarization vectors for a pure and nanodoped system are calculated and the strong influence of spontaneous polarization on magnetic threshold field is revealed as well as on electric field. We assume that the smectic layers consist of uniform planes with a fixed orientation and the system is free from dislocation of constant layer thickness due to nanoparticles. Comparing the obtained results for a nanodoped one with the transition behavior in a pure cell shows the significant influences of nano dispersions on ordering behavior even at low concentrations. The results exhibit the dependence of magnetic threshold field on the presence of ferroelectric nanoparticles and the spontaneous polarization as well as some other material and external parameters. The boundaries for the stability of the uniform configuration of a pure and nanodoped SSFLC system are determined. It is also found that for a SSFLC structure, beyond a critical thickness between the boundary plates of the cell, the Fredericks threshold fields would not be sensitive to the cell thickness.