  Experimental and theoretical studies of a smectic-hexatic transition in
freely suspended films of 54COOBC compound are presented. X-ray investigations
revealed a discontinuous first-order transition into the hexatic phase.
Moreover, the temperature region of two phase coexistence near the phase
transition point diminishes with film thickness. The coexistence width
dependence on film thickness was derived on the basis of the Landau mean-field
theory in the vicinity of the tricritical point (TCP). Close to TCP the surface
hexatic ordering penetrates anomalously deep into the film interior.
