Proton magnetic resonance study of the low-temperature phase transition in a LiNH4SO4 single crystal Original Research Article

The proton NMR line width and spin-lattice relaxation times for LiNH4SO4 single crystal were studied at low temperature range of 6 and 280 K. The changes in the proton relaxation behavior near the phase transition temperature indicates a change in the state of internal motion at the transition. The molecular motions obtained by the spin-lattice relaxation processes were found to be determined by molecular reorientation of the NH4 ions in phases III, IV, and V. We also confirmed that the phase transitions occur at 26 and 133 K.