Conduction-electron-spin polarization near Mn impurities in Cu

Abstract

The perturbation of ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}$ hyperfine fields by nearby Mn impurities was measured by detecting copper satellite-nuclear-resonance lines. Three satellites were found and were attributed to the resonance of copper nuclei in second-, third-, and fourth-neighboring shells to an impurity. The hyperfine-field perturbation of first-neighbor nuclei and the envelope of the oscillating disturbance at distant neighbors can be estimated from other information. We have expressed the experimental results in a form which can be readily compared with free-electron calculations of conduction-electron-spin polarization by magnetic impurities. The Rudermann-Kittel-Kasuya-Yosida (RKKY) mechanism is apparently too weak to account for the observed polarization, and we have calculated the conduction-electron-spin disturbance which arises from hybridization of conduction states with the impurity $d$ states. Near the impurity this computed spin polarization is not particularly sensitive to details of the model. It depends primarily only on the impurity density-of-states bandwidth, and agreement with experiment is very good for a halfwidth of about 0.2 eV.