Dielectric relaxation in a ferroelectric liquid crystal

Ph. Martinot-Lagarde , Geoffroy Durand

We present an analytic calculation of the normal modes of distortion induced by a small transverse A.C. electric field on a ferroelectric liquid crystal close to its transition temperature Tc between the smectic A and C* phases. These normal modes are superpositions of electric polarization and angular molecular distortion. Compared to a previous work of Blinc and Zeks, we assume that the losses are diagonal for the normal modes. The new prediction is that the soft mode in the A and C* phase goes continuously into pure polarization modes far from Tc. Flexoelectric effects eventually could be observed close to Tc, in the amplitude and frequencies of the A.C. contribution of the normal modes to the dielectric constant, although for zero frequency the sum of these contributions remains zero.

Mots clés: dielectric polarisation; dielectric relaxation; ferroelectric materials; flexoelectricity; liquid crystal phase transformations; smectic liquid crystals; soft modes

Domaines: Articles anciens

Ph. Martinot-Lagarde, Geoffroy Durand. Dielectric relaxation in a ferroelectric liquid crystal. Journal de Physique, 1981, 42 (2), pp.269-275. ⟨10.1051/jphys:01981004202026900⟩. ⟨jpa-00209008⟩