Magnetic Moment Distributions in Dilute Nickel Alloys

A neutron scattering technique has been developed which enables the spatial distribution of the magnetic moment disturbance around an impurity atom in a ferromagnet to be examined over a distance of several Angstroms. Measurements show that when vanadium or chromium is added dilutely to nickel the resulting magnetic disturbance occurs not only at the impurity atom sites themselves, but also on the neighboring nickel sites. In fact, most of the change in saturation magnetization observed on alloying is due to a decrease in the moments on nickel atoms in the vicinity of solute atoms rather than to changes in moment at the impurity atom positions. On the other hand, if iron or manganese is added dilutely to nickel the moment disturbance appears to be confined to the solute atoms. These results are discussed in terms of a theory suggested by Friedel.