Nuclear spin relaxation and correlated diffusion of impurities
نویسندگان
چکیده
From NMR line width experiments on the diffusion of Naf and Li+ ions in AgBr activation enthalpies of h(Naf) = (1.21 f 0.05) eV and h(Lif) = (0.88 f 0.04) eV are deduced for NMR correlation times. Correlation effects in impurity diffusion are inferred from a comparison of the NMR data to results from conductivity and tracer diffusion. Naf ions are found to perform an almost perfect random walk. In contrast, Li' ions are shown to be fast diffusing impurities in AgBr with vacancy jump frequencies larger than those of the host cations.
منابع مشابه
Quantum Theory of Spin Diffusion
It has been recognized that the notion of spin diffusion due to the exchange-type interaction between spins is very useful to describe a number of experiments on the nuclear spin relaxation in a crystal containing paramagnetic impurities/l and on the critical scattering of neutrons by a ferromagnet. 2l It has been assumed there that the z-component of the magnetization density, A1°(R), would ob...
متن کاملProton Dipolar Spin–Lattice Relaxation in Nano-channels of Natrolite
The 1H nuclear magnetic resonance (NMR) spectra and the dipolar spin-lattice relaxation time T1D for 1H in the natural natrolite (Na2Al2Si3O10·2H2O) have been measured in the temperature range of 190-390 K. From the temperature transformations of 1H NMR spectra, it follows that at T > 300 K, the diffusion of water molecules along the nano-channels is observed. From experimental T1D data, it fol...
متن کاملSpin 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 the presence of paramagnetic impurities in solids. The obtained diffusion equation 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 di...
متن کاملSpin-lattice relaxation of a nuclear antiferromagnet
2014 We consider the influence of antiferromagnetic nuclear ordering on the spin-lattice relaxation of the nuclear dipolar energy by paramagnetic impurities. The predictions are different depending whether the correlation time 03C4c of the spin-lattice coupling is shorter or longer than T2. When 03C4c ~ T2, relaxation is slower in the antiferromagnetic than in the paramagnetic state. When 03C4c...
متن کاملRelaxation Mechanisms and Effects of Motion in Albite (NaA1Si308) Liquid and Glass: A High Temperature NMR Study
The nuclear magnetic relaxation of 23Na and z9Si in albite glass and liquid has been studied from 800 K to 1400 K. The dominant spin-lattice relaxation mechanism for 23Na is found to be nuclear quadrupole interaction arising from the Na + diffusion. The activation energy of the Na diffusion is found to be 71 _+ 3 kJ/mol, in close agreement with the results on electrical conductivity and on Na s...
متن کامل