NMR spin-lattice relaxation study of Cs1‑x(NH4)xH2PO4

Abstract

Spin-lattice relaxation time T1 for 31P was measured as a function of temperature at 28.2 MHz in a powder sample of Cs1-x (NH4) x H2PO4 (CADP) crystallized from a solution with a molar ratio x = 0.2. This crystal has the same structure as CsH2PO4 (CDP), which exhibits a low-temperature pseudo-one-dimensional ferroelectric phase transition at 159 K and a superionic transition at 504 K on heating. The measured temperature dependence is explained in terms of hydrogen bond dynamics.