Complementary studies of de Vries type SmA∗ phase

Two liquid crystalline compounds showing ferroelectric properties have been investigated. Both substances exhibit the so-called de Vries phase. To study the paralectric-ferroelectric transition X-ray diffraction, electrooptic and dielectric studies have been done. It was found that small layer shrinkage is accompanied by a strong electroclinic effect in paraelectric phase and at the paralectric-ferroelectric transition.