Concentration Dependence of the Range of Spin Polarization in Pd(Fe) Alloys

Abstract

According to recent neutron‐scattering experiments of Low and Holden, the conduction‐electron spin polarization around a magnetic Fe impurity in Pd has a very long range ∼10Å. This long range has been attributed to the large exchange enhancement in Pd. Another interesting aspect of this problem, although it has received less attention, is that the range of the spin polarization, the total giant moment per impurity atom, and the Pd high‐field susceptibility depend very sensitively on the concentration of the magnetic impurity. For example, neutron scattering shows that an increase in the Fe concentration from 0.26% to only 4.0% reduces the range from 10 to 1 Å. We understand this very sharp dependence of the range by taking into account the increase in spin splitting of the host Pd bands with increasing Fe concentration. The expression for the q‐dependent susceptibility for split bands is generalized to include the effects of the detailed structure of electron interactions and is used to obtain a quantitative fit to the data.