Dipolar ordering and glassy freezing in a clathrate

The dielectric permittivity of methanol-P-quinol clathrates has been studie d as a function of temperature, frequency and methanol concentration. Highe r concentrated samples undergo a first-order antiferroelectric transition, lower concentrated ones are established as dipole glasses. The main structu ral motif are ferroelectric chains, respectively chain segments. The largel y different strength of the intrachain and the interchain coupling, the fru stration leading to the glass state. and the relaxational dynamics are inte rpreted in terms of the dipole-dipole interaction in combination with the r hombohedral symmetry of the host lattice.