Effect of Mn on the structural, energetic, electronic and elastic properties of ordered L1₀ FePt Alloy

Department of Physics, University of Fort Hare, Private Bag X1314, Alice, 5700, Eastern Cape, South Africa

Abstract

This study performed systematic ternary substitution of Mn into the ordered L1₀ bulk FePt alloy to investigate its effect on structural, energetic, electronic and elastic behaviour at 0 K. Three ternary compositions were considered; namely Fe_0.7Mn_0.3Pt, Fe_0.5Mn_0.5Pt and Fe_0.3Mn_0.7Pt. Ab initio calculations based on the density functional theory (DFT) formalism were employed using the CATEP module within the Materials Studio program. The findings of this study showed that Mn substitution promotes thermodynamic stability and isotropy due to the decreased enthalpy of formation and universal anisotropy index. The Fe_0.3Mn_0.7Pt system was predicted to be the most favourable composition, due to less volume deviation from the pristine ordered FePt, the highest Debye temperature and the presence of a deep pseudo gap around the Fermi level.