Dipolar ordering and glassy freezing in methanol-beta-hydroquinone-clathrate - art. no. 224202

The dielectric, structural, and thermodynamic properties of single crystals of methanol-beta -hydroquinone clathrates have been studied as function of temperature and of the concentration x of the polar guest molecules. At hi gher temperatures the dielectric response along the threefold crystal axis is of the quasi-one-dimensional Ising type. At lower temperatures the highe r concentrated samples order antiferroelectrically whereas the lower concen trated ones freeze into dipole glasses. The behavior is interpreted in term s of the methanol dipole moments coupled by the electric dipole-dipole inte raction which is highly frustrated because of the rhombohedral symmetry of the lattice. The dielectric relaxations have been analyzed.