We have observed the nuclear resonances of five shells of Cu atoms which are near neighbors to single Fe impurities in dilute alloys of CuFe. Each of the satellite shifts are linear in external magnetic field from 7 to 63 kG, and three have positive shifts while two have negative shifts. From line shape, intensity, and width, four of these satellites are identified as being due to the first, second, third, and fourth shells of neighbors. The satellite shifts, which are proportional to the conduction-electron spin density, are compared with the predictions of various theories in order to determine the values of the parameters involved in characterizing dilute magnetic alloys. It is found, using the theory of Jena and Geldart, that a good explanation of the spin density cannot be given unless the crystal-field splitting of the Fe $d$ levels is taken into account. The energy-level parameters obtained are: the crystal-field splitting, 0.5 eV; virtual level width, 0.7 eV; Coulomb splitting, 5.6 eV. The magnetization distributed in the electron gas is shown to be aligned antiferromagnetically with the moment on the Fe atom and to be about nine times smaller than this moment. Four of the satellites were observed down to well below the 29-K Kondo temperature, and, in each case, the shift scaled as $\frac{1}{\mathrm{}(T+29\mathrm{})\mathrm{}}$. Thus, the spin density has the same temperature dependence as the bulk susceptibility, showing that contrary to some speculation there is no drastic change in the spatial polarization associated with the Kondo condensation.

• Received 10 March 1975

DOI:https://doi.org/10.1103/PhysRevB.13.379