Two-time clock NMR observation of the ferroelectric transition in the organic compound cyclohexane-1,1′-diacetic acid

Abstract

The ferroelectric transition in the molecular organic ferroelectric material cyclohexane-${1,1}^{\ensuremath{'}}$-diacetic acid has been studied with a ${}^{1}H$ NMR two-time clock experiment. On the spin-lattice relaxation time scale ${(10}^{8}\mathrm{Hz})$ the molecular motions are observed as slow in both the paraelectric and the ferroelectric phase so that the instantaneous value of the crystal symmetry is observed in both phases and no symmetry breaking effectively takes place at ${T}_{c}.$ On the kHz time scale of the NMR line shape and the dipolar relaxation time experiments, the phase transition is observed and confirms the model of a dynamically disordered structure in the paraphase.