Direct electrical measurement of the permanent polarization of a ferroelectric chiral smectic C liquid crystalReportar como inadecuado




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Abstract : A sample of p-Hexyl-Oxy-Benzylidne-p-Amino-2-Chloro-Propyle-Cinnamate, Chiral liquid crystal, is oriented in the ferroelectric smectic C-phase by a square wave field ± E; its permanent polarization orients itself from + P to — P in a time adjustable with E. This time is chosen to obtain an induced transient current, due to the polarization variation, distinguishable from the charge and conduction currents in the sample. The integral of this bump of current gives the value of P : P = 5 × 10-2 Debye per molecule and radian of the molecular tilt angle. This method gives the first direct measurement of P and its variation versus the temperature.

Keywords : ferroelectric materials organic compounds smectic liquid crystals ferroelectric chiral smectic C liquid crystal induced transient current charge conduction currents molecular tilt angle permanent polarisation direct electrical measurement





Autor: Ph. Martinot-Lagarde

Fuente: https://hal.archives-ouvertes.fr/



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