Experimental evidence for the relaxation coupling of all longitudinal Li magnetization orders in the superionic conductor LiGePS.

This contribution addresses the experimental proof of the relaxation coupling of the Li (I = 3/2) longitudinal magnetization orders in the solid-state electrolyte LiGePS (LGPS). This effect was theoretically described by Korb and Petit in 1988 but has not yet been shown experimentally. In a 2D-T/spin-alignment echo (SAE) experiment, the inverse Laplace transformation of the spectral component over two time dimensions revealed the asymmetric course of the spin-lattice relaxation following from the coupling of all longitudinal orders. These observations were supported by Multi-quantum-filter experiments and by simulations of the 2D-T/SAE experiment with a lithium spin system. Since the asymmetric relaxation effects are directly dependent on the velocities and degrees of freedom of ion motion they could be used especially in fast Li-ion conductors as a separation tool for environments with different mobility processes.