A neutron diffraction study on deuterated rochelle salt in the paraelectric phase

Abstract

The crystal structure of Rochelle salt was refined at two temperatures of paraelectric phase by using three-dimensional neutron diffraction data from deuterated single crystal. The high temperature (40°C) structure exhibits enhanced anisotropic thermal motion about particular deuterium atoms while the low temperature (-195°C) structure shows quite normal state with lessened anisotropic thermal behaviors. These anisotropies are further refined by split-atom model and it was shown that split-atom model gives better agreement. Based on these structures, phase transition scheme was examined. Previous model of the phase transition does not contradict to the present result but needs some modifications.