Spin diffusion in multiple pulse spin-locking in solids containing paramagnetic impurities

摘要

Spin diffusion and spin-lattice relaxation in solids containing paramagnetic impurities under influence of a multiple-pulse spin-locking radio-frequency sequence are studied theoretically and experimentally. The diffusion equation obtained provides a clue for determination of the time dependent magnetization. The spin-lattice relaxation time is calculated as a function of the correlation time and multiple-pulse field parameters. From the experimental data the spin diffusion coefficient, the radius of the spin diffusion barrier, and the correlation time for very slow molecular motion in polycrystalline (C_2F)_n system are estimated and found to be D ～ 7.1 × 10~(-12) cm~2/s, r_c ～4.8 × 10~(-10) m, and τ_c ～ 10.2 μs, respectively.