Dielectric studies of the smectic C*-smectic a transition of a ferroelectric liquid crystal with high spontaneous polarization

The static dielectric constant ∊⊥ in the smectic A and the smectic C* phase of the ferroelectric liquid crystal 4-(3-methyl-2-chlorobutanoyloxy)-4'-heptyloxybiphenyl was determined. Strong pretransitional effects were observed in the smectic A phase. When the Goldstone mode contribution in the smectic C* phase is quenched by the application of a dc electric field, a cusp like behaviour of ∊⊥ at the smectic C*-smectic A transition can be observed which is similar to solid ferroelectrics. The maximum in ∊⊥ was found to shift to higher temperatures with increasing dc field strength in agreement with the electric field dependence of the transition temperatures reported previously.