The rotator phase of ${\mathrm{C}}_{24}$${\mathrm{F}}_{50}$ has been characterized in its calorimetric as well as in its elastic properties. To perform the elastic characterization we took advantage of a polytetrafluoroethylene-induced-alignment crystal-growth technique. Special interest is paid to the rotator phase and the premelting behavior therein as reflected by the elastic stiffness coefficients ${\mathit{c}}_{33}$ and ${\mathit{c}}_{44}$. The anomalous elastic behavior is interpreted in the frame of the Landau theory. The premelting process is related to molecular conformational defects.

• Received 20 October 1994

DOI:https://doi.org/10.1103/PhysRevB.51.3353