THERMAL DIFFUSE-SCATTERING IN TIME-OF-FLIGHT NEUTRON-DIFFRACTION STUDIES ON SBN AND TSCC SINGLE-CRYSTALS

Thermal diffuse scattering (TDS) from single crystals of barium stront ium niobate (SBN) and from a partly deuterated single crystal of tris( sarcosine) calcium chloride (TSCC) measured on the time-of-flight (TOF ) Laue single-crystal diffractometer DN-2/IBR-2, Dubna, Russia, are pr esented. Various characteristic distributions of the TDS were measured and could be interpreted for the elastically (nearly) isotropic SBN c rystals as well as for the anisotropic TSCC sample in accordance with the theory. The velocities of sound propagation are determined in both cases. Temperature-dependent changes of the TDS are qualitatively ana lysed for SBN crystals.