[en] The authors have studied the quadrupole splittings and relaxation rates of ⁷Li and ⁶Li in single crystals of LiAlSiO₄ from 77K to 760K. The data reveal two diffusion processes: 1D diffusion along the main and secondary channels and hopping of Li ions between different channels. Some samples intentionally doped with Fe-ions are used to check theoretical predictions about relaxation by 1D diffusion to paramagnetic impurities. (Auth.)

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[en] Previous NMR studies in RbAg₄I₅ have been supplemented by additional measurements on the ⁸⁷Rb nuclei and extended to the mobile Ag ion. The thermally activated relaxation rates of the stationary and the mobile ions show remarkable differences in the overall temperature behavior as well as at the 208 K phase transition. A possible interpretation is given in terms of ''trial and error'' hopping and configurational response of the mobile Ag ions. (Auth.)

[en] The authors report the first use of nuclear magnetic resonance to investigate the dynamic behaviour of dilute (110) off-center Ag⁺ defects in RbCl. The ⁸⁷Rb nuclear spin relaxation data provide the correlation time of the localized motion of the Ag⁺ dipoles. (Auth.)

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[en] We present results of ¹⁷O and ^63,65Cu nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) studies in the normal and superconducting state of the 82-K superconductor YBa₂Cu₄O₈. The various components of the Cu and O Knight-shift tensors show strong but similar temperature dependences over the temperature range from 8.5 to 300 K in both the CuO₂ planes and the chains, supporting the picture that there is only one spin component in the planes and the chains, although with different susceptibilities. The oxygen data obey the Korringa relation. This may be interpreted as Fermi-liquid behavior of the electronic system far away from the antiferromagnetic wave vector. The temperature dependence of both the planar Cu and O shift tensors and the planar Cu spin-lattice relaxation rate suggest the opening of a pseudo-spin-gap well above T_c. The very different temperature dependence of 1/T₁ at the planar O and Cu sites points to the reduced role of the antiferromagnetic correlated spin fluctuations at the O site. The data favor the conclusion that YBa₂Cu₄O₈ is a d-wave superconductor. Evidence is provided by three data sets: the chain Knight shifts, the ratio of the planar copper and oxygen relaxation rates, and the individual low-temperature behavior of these rates