Ion Bump in the Ferroelectric Liquid Crystal Domains Reversal Current

Abstract

In ferroelectric liquid crystal cells, variable electric field is applied to obtain the electro-optical switching. The transient currents through the cell show a complex behavior. A bump may appear¹ in addition tothe well known bumps corresponding to the induced polarization variation and the reversal of spontaneous polarization in the bulk and at the cell surfaces. We explain different possible models for thisbump. Experimental studies were conducted on the amplitude and the peak time of this bump forvarious compounds in different phases. From the obtained results, we conclude that this bump corresponds to the movement inside the cell of ions stuck on the electrodes. We found ionic impuritiesallowing to control the amount of these stuck ions.