Resonant x-ray scattering study of the antiferroelectric and ferrielectricphases in liquid crystal devices - art. no. 021705

Resonant x-ray scattering has been used to investigate the interlayer order ing of the anti ferroelectric and ferrielectric smectic C* subphases in a d evice geometry. The liquid crystalline materials studied contain a selenium atom and the experiments were carried out at the selenium K edge allowing x-ray transmission through glass. The resonant scattering peaks associated with the anti ferroelectric phase were observed in two devices containing d ifferent materials. It was observed that the electric-field-induced anti fe rroelectric to ferroelectric transition coincides with the chevron to books helf transition in one of the devices. Observation of the splitting of the antiferroelectric resonant peaks as a function of applied field also confir med that no helical unwinding occurs at fields lower than the chevron to bo okshelf threshold, Resonant features associated with the four-layer ferriel ectric liquid crystal phase were observed in a device geometry. Monitoring the electric field dependence of these ferrielectric resonant peaks showed that the chevron to bookshelf transition occurs at a lower applied field th an the ferrielectric to ferroelectric switching transition.