63Cu spin lattice relaxation in Cu-Mn and Cu-Cr. Electron spin dynamics

The 63 Cu nuclear spin lattice relaxation rate (T 1 ) -1 in Cu-Mn and Cu-Cr dilute alloys, measured between 0.32 and 20K, are interpreted in the light of recent spin diffusion studies done by the authors (1972) in Cu-Mn alloys. It is shown that, the most important impurity contribution to (T 1 ) -1 is through the RKY coupling with the transverse fluctuations of the impurity moment. The impurity spin relaxation rate involved in the NMR data is different from the ESR linewidth and is associated with simple impurity fluctuations.