Positive Muons in Copper: Detection of an Electric-Field Gradient at the Neighbor Cu Nuclei and Determination of the Site of Localization

This is the authors' abstract. We don't add key points for this paper.

The depolarization of positive muons implanted in single crystals of Cu has been studied as a function of applied magnetic field and of crystal orientation at 20 and 80 K. The depolarization due to static dipolar magnetic interactions with the Cu nuclei shows an unusual dependence on magnetic-field strength which can be explained by quadrupole interactions of the neighbor Cu nuclei in an electric-field gradient. The muon is self-trapped at the octahedral interstitial site. The nearest neighbors are displaced away from the muon by {~} 5%.