Influence of oxygen and nitrogen doping on the structure and magnetic properties of FePt alloy: First principles calculations

We studied the magnetic and electronic properties of L10-FePt alloy interstitial doped by oxygen or nitrogen using tetragonal distortion. We applied the density functional theory from first principle until the exchan-ge-correlation energy; the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) was used. We found that the magnetocrystalline anisotropy MCA significantly increased for FePt:NPt and our obtained value was 3.879 meV, which exceeds the pristine value. The anisotropy field Ha, saturation magnetization Ms and the energy product (BH)maxwere nearly close to the pristine value. These parameters can be tuned for practical applications. Calculations of formation energy Efor reveal promotion of stability with doping. Density of state calculations showed strong hybridization of d-orbits with 2p orbits of O or N. Moreover, with doping, there was an enhancement of energy states at Fermi level.