The diffusion mechanism of Cu+ was studied by means of nuclear magnetic resonance, powder X-ray diffraction and alternating-current conductivity measurements. It was found that the satellite spectra of the 63Cu and 27Al nuclear magnetic resonance varied anomalously with temperature. The quadrupole coupling constant of the 63Cu nucleus, and the asymmetrical parameter of the 27Al nucleus, changed markedly with decreasing temperature. The quadrupole coupling constant of the 27Al nucleus was little changed. Via calculations of the electric field gradient tensors, it was confirmed that these temperature dependences were produced by Cu+ diffusion and by variation of the lattice constants. The diffusion path of Cu+ was confirmed by nuclear magnetic resonance experiments: that is, the Cu+ jumped between normal sites via an interstitial site. The conductivity was evaluated by assuming that the diffusion mechanism and its value were consistent with the observed alternating-current conductivity.

Diffusion Mechanism of Copper(I) Ion in CuAlBr4 Studied by Nuclear Magnetic Resonance. Y.Tomita, K.Kobayashi, H.Ohki, K.Yamada, T.Okuda: Solid State Ionics, 1999, 126[1-2], 121-31