NMR Study in Rochelle Salt

Abstract

The angular dependence of the proton magnetic resonance absorption of a Rochelle salt single crystal has been measured. The experimental second moments are compared with the theoretical curves, as calculated for the structures proposed so far. Lösche's model was found to reproduce the qualitative form of the angular dependence, whereas the other structures gave no agreement at all. The occurrence of transitions in the proton magnetic absorption line widths at +24°C and below —20°C demonstrates that the assumption of protonic motion, upon which the dynamic theories of ferroelectricity in Rochelle salt are based, is essentially correct.