KINK SWITCHING IN FERROELECTRIC FREESTANDING FILMS WITH HIGH SPONTANEOUS POLARIZATION

The dynamics of a Sm-C director held in an a.c. electric field has be en studied by means of light scattering. The scattering of resonance t ype has been observed by the variation of field frequency at fixed tem peratures. The resonance scattering is supressed in high electric fiel ds, at low temperatures in the Sm-C phase, and in films thinner than a threshold value N-0. A theory of director switching is proposed that consistently describes the observed anomalies. The film parameters vi scosity, dielectric anisotropy, and polar film anisotropy are determin ed. This work provides evidence that the Sm-G structure in the bounda ry layers and the thin films of materials with high spontaneous polari zation correspond to the weak anisotropic state predicted early.