Spin diffusion in pure multiple-pulse NQR

We present a detailed theoretical and experimental NQR multiple-pulse spin- locking study of spin-lattice relaxation and spin diffusion processes in th e presence of paramagnetic impurities in solids. The obtained diffusion equ ation was obtained allows to find the time dependence of the magnetization in the effective field. The spin lattice relaxation times were calculated, both for direct and diffusion regimes, as functions of the correlation time and multiple-pulse parameters. Measurements of relaxation times in rotatin g frame allow to determine the diffusion coefficient and the radius of the diffusion barrier in gamma-irradiated polycrystalline samples of NaClO3.