Field driven ferroelectric–ferroelectric transition: Evidence of antiferroelectric Goldstone mode in the phase

The field (E) driven ferroelectric–ferroelectric (F+–F−) transition process in ferroelectric SmC∗ and antiferroelectric SmC A ∗ phases of liquid crystalline material viz. 4′-octyloxybiphenyl-4-carboxylate (MOPBIC) has been studied by measuring dielectric permittivity at different polarizing states during the transition. It is observed that, the interaction between E and ferroelectric polarization, in the SmC∗, phase governs the F–F transition, whereas in the SmC A ∗ phase, the combination of successive coupling of E with antiferroelectric polarization and dielectric anisotropy is responsible for the same transition. In the SmC A ∗ phase there exists antiferroelectric Goldstone mode in analogy with the ferroelectric Goldstone mode in the SmC∗ phase.