Cross-relaxation of 8Li+ in copper

The “cross-relaxation” method (also called “level-crossing resonance” or “avoided level-crossing”) is a powerful technique that can be used to provide detailed structural and site information on impurities in materials. In this paper, we report on the development of the cross-relaxation technique for Li+8 at the β-detected nuclear magnetic resonance (β-NMR) facility located in TRIUMF in Vancouver. The measurements were carried out on a 〈110〉 Cu single crystal where the relaxation rate of the Li8 polarization was monitored as a function of the applied longitudinal magnetic field. The occurrence of cross-relaxation, at a particular magnetic field, between the Li8 and the surrounding nuclei is evident as a resonant enhancement of the relaxation rate at the level crossing field. We discuss inferences about the site and structure of Li+8 in Cu from this data.