Direct measurements by the pulse pyroelectric technique of the soft-mode relaxation times on both sides of the smectic A–C* transition

Abstract

The submicrosecond pulse pyroelectric technique has been applied to the measurements of the soft mode relaxation times on both sides of the ferroelectric smectic A–C* phase transition for two ferroelectric liquid crystals, a room temperature multicomponent mixture with high spontaneous polarisation; and a compound with polarisation changing its sign at a certain temperature. Inverse relaxation times seem to obey Curie-type behaviour, at least on the smectic A side of the transition. “Tilt-viscosity” coefficient γ9 has been calculated for both the materials.