2-TIME CLOCK NMR OBSERVATION OF THE FERROELECTRIC TRANSITION IN THE ORGANIC-COMPOUND CYCLOHEXANE-1,1'-DIACETIC ACID

The ferroelectric transition in the molecular organic ferroelectric ma terial cyclohexane-1,1'-diacetic acid has been studied with a H-1 NMR two-time clock experiment. On the spin-lattice relaxation time scale ( 10(8) Hz) the molecular motions are observed as slow in both the parae lectric and the ferroelectric phase so that the instantaneous value of the crystal symmetry is observed in both phases and no symmetry break ing effectively takes place at T-c. On the kHz time scale of the NMR l ine shape and the dipolar relaxation time experiments, the phase trans ition is observed and confirms the model of a dynamically disordered s tructure in the paraphase.