Resonant x-ray scattering at the Se edge in liquid crystal free-standing films and devices

Resonant x-ray diffraction was carried out at the Se K edge in thick free-s tanding films of a selenophene liquid crystalline material, revealing detai l of the structure of the ferro-, ferri-, and antiferroelectric phases. The ferrielectric phase was shown to have a three-layer superlattice. Moreover , the structure of a lower temperature hexatic phase was established. For t he antiferroelectric phase, investigations were also carried out in a plana r device configuration. The device allowed resonant scattering experiments to be carried out with and without the application of an electric field and resonant data are compared with electro-optic measurements carried out on the same device. (C) 2000 American Institute of Physics. [S0003-6951(00)015 13-8].