Diffusion processes in solid Li-Mg and Li-Ag alloys and the spin-lattice relaxation of⁸Li

Microscopic Dynamics of Li+ in Rutile TiO2 Revealed by 8Li β-Detected Nuclear Magnetic Resonance

“…If quadrupolar fluctuations are the dominant source of relaxation, as would be expected for 8 Li + diffusion, then on the low temperature side of the T 1 minimum, where the fluctuations are slow compared to ω L , the relaxation may be intrinsically biexponential for spin I = 2. 58,59 However, these Redfield-theory calculations of R(t, t ) differ in several key assumptions from our situation, specifically: 1) the initial state of the optically polarized 8 Li spin is quite different; 47 2) we are not always in the extreme high field limit; and 3) one dimensional hopping yields a non-Debye fluctuation spectrum. 67,68 Moreover, above the T 1 minimum, where the fluctuations are fast, the biexponential should collapse to a single exponential, 58 which is certainly not the case here, particularly for the low field data.…”

Tracer diffusion measurements in solid lithium: a test case for the comparison between NMR in static and pulsed magnetic field gradients after upgrading a standard solid state NMR spectrometer

“…In the case of self-diffusion, which we are concerned with here, f is a constant depending on the crystal structure and the diffusion mechanism. The coefficient of uncorrelated diffusion can be determined by spin-lattice relaxation (SLR) measurements [35] which were done for solid lithium by 7 Li-NMR ( [36] and references therein) and b-NMR on 8 Li [2,37]. Spin-lattice relaxation measurements provide the average residence time t r of the Li atoms.…”

“…Assuming a definite diffusion mechanism and adopting its correlation factor, a calculation of the tracer diffusion coefficient D T from the diffusion coefficient of uncorrelated diffusion D uc is possible. In case of Li self-diffusion in solid lithium a combined process of monovacancy and divacancy diffusion has been assumed [2,36,37]. Monovacancy (1V) diffusion in a bcc lattice has a correlation factor of f 1V ¼ 0:727 and divacany (2V) diffusion has a correlation factor of, e.g., f 2V ¼ 0:347 (2N-4N-2N configuration, i.e.…”

β‐Radiation Detected Li Diffusion in the Fast Ionic Conductor Li3N

“…Detailed diffusion studies by the neutron-activation B-NMR technique were done in Li metal [4] and binary Li alloys [ 5 ] . In these systems which have cubic structure diffusion is isotropic.…”