FREQUENCY-DEPENDENT SWITCHING BEHAVIOR UNDER TRIANGULAR WAVES IN ANTIFERROELECTRIC AND FERRIELECTRIC CHIRAL SMECTIC PHASES

A realistic model structure of the ferrielectric phase is proposed by taking into account the apparent tilt angle measurements. On the basis of the model, the electric and optical responses are investigated in the ferrielectric SmCγ* as well as in the antiferroelectric SmCA* phases of MHPOBC (C8H17O-COOC*H(CH3)C6H13) under triangular waves of various frequencies. At low frequencies, D-E curves show double and triple hysteresis loops characteristic of the antiferroelectric and the ferrielectric phases, respectively. T (transmittance)-E curves also reveal similar hysteresis loops. With increasing frequency, the direct switching between the two ferroelectric states occurs without passing through the antiferroelectric state or the ferrielectric states. The complicated frequency dependence is interpreted based on the spatially inhomogeneous domain switching. © 1990 The Japan Society of Applied Physics.