The behavior of localized moment of Ni in Ni–Cu alloy system

Magnetic scattering amplitudes of Ni-Cu alloys with 11.5 and 38.0 atomic percent of Cu were determined by means of the polarized neutron diffraction technique. They were analyzed using the form factor associated with Ni atoms in pure Ni state to give the mean localized moment per Ni of these alloys as 0.638±0.011 µ_B and 0.321∓0.008 µ_B respectively. The mean diffuse spin polarization per atom were determined also as —0.079±0.011µ_B and —0.020±0.006µ_B respectively. The behavior of the Ni localized moment in this alloy system can be explained reasonably well by the nearest neighbor environment model in which the localized moment decreases linearly with reduction rate of 0.038µ_B per added Cu atom in its nearest neighbor position so far as the number of nearest neighbor Ni atoms remains more than or equal to eight, whereas the number becomes less than eight, the central Ni loses its moment completely.