Results of inelastic neutron scattering experiments between 300 K and 900 K on the relaxor ferroelectric PbMg<Subscript>1/3</Subscript>Nb<Subscript>2/3</Subscript>O<Subscript>3</S ubscript> are presented. Within a mode-coupling analysis the data are consistent with the observation of a strongly damped quasi-optic excitation. It is demonstrated that below T <Subscript>d</Subscript> ≈...</subscript><//s></subscript></subscript></subscript>

Using coherent inelastic neutron scattering we have investigated the phonon dispersion relation of bulk hexagonal 6H-SiC. The complete set of phonon branches has been determined along the Γ−A and 14 out of 36 branches along the Γ−M direction. The experimental data are compared to ab initio...