Average Magnetic Moment of Mn Impurities in Ferromagnetic Ni–Co Alloys

Abstract

The average magnetic moments of Mn atoms dissolved in fcc Ni–Co alloys have been determined as a function of concentration of host alloys. The measurements were made with alloys containing 2 atomic percent Mn at about 300 K and 100 K by means of diffuse scattering of polarized neutrons. The average magnetic moment of Mn, which is about 3 μ_B in pure Ni, decreases with increasing Co concentration and changes its direction at about 50 atomic percent Co from parallel to antiparallel to the bulk magnetization of host alloys. This behavior agrees qualitatively with the theoretical results obtained under the assumption of the extended coherent potential approximation, but a quantitative discrepancy is found especially near Co concentration of about 20 to 40 atomic percent.