Influence of Mn Doping on Local Spin Moments and Stacking Fault Energies in Co(Mn) Alloys

We report on the results of first principles calculations investigating the influences of Mn doping on the local moments and stacking fault energies (SFEs) in the Co95.8Mn4.2 and Co91.6Mn8.4 systems as compared to pure face-centered cubic Co. A supercell was developed to maintain periodicity in calculations, provide a simple relaxation mechanism, and allow for easy expansion to accommodate different concentrations of Mn. Calculations to determine the generalized SFE were performed on relaxed and non-relaxed systems in both ferromagnetic and nonmagnetic states. Analysis revealed fluctuations in the magnetic moments that are closely tied to the relaxation state and faulting state of the system. In the case of systems containing Mn, we observed a dependence of the SFE on the location of the Mn atom(s) within the supercell relative to the stacking fault interface and a strong induced magnetic moment for these atoms.