Measurements of electron-spin density near Co atoms in Cu

Abstract

We report nuclear-magnetic-resonance studies of Cu Co in which we resolve and identify satellites due to three shells of Cu near neighbors around isolated Co impurities. The satellite positions show that the spatial form of the spin polarization oscillates with distance and that the conduction electrons on these atoms contribute about —8% of the total impurity susceptibility. The splittings are measured from 1.5 to 450°K and from 6.4 to 63 kG and compared with the susceptibility $\chi$ of singles. The width of the main line is decomposed into contributions ${\Delta }_1$ and ${\Delta }_2$ from isolated Co atoms and pairs of Co atoms, respectively, by use of the temperature variation of the splitting and of the pair susceptibility ${\chi }_2$. the theory of Walstedt and Walker is used to show that ${\Delta }_1$ agrees with what one would expect from the satellite splittings, and that $\frac{{\Delta }_1}{{\Delta }_2}$ is reasonable in terms of the magnitude and temperature dependence of ${\chi }_1$ and ${\chi }_2$. The results are scaled to CuFe to show that much of the observed linewidth anomaly is of the same origin, and must be included before possible conclusions can be made about Kondo correlation effects.