A phase diagram of the surface melting type, qualitatively new for liq
uid crystals, has been observed in free-standing films: the SmC- Sm C
-ferri and Sm C-ferri-SmCA phase transitions can be shifted to lower t
emperatures by decreasing the number of layers. This phenomenon is exp
lained by the influence of the depolarizing fields. (C) 1995 American
Institute of Physics.