We performed ab-initio electronic structure calculation in Co doped Fe/MgO interface on the basis of density functional theory. Two different slab models are considered, depending on the place of Co atom; at the interface and in the Fe layer. With using atomic forces, we obtained the optimized structure at the interface and discussed the layer distance of interface and the local structure around Co. Spin magnetic moments on Fe and Co atoms are also discussed. In the band dispersion at the Fermi level, distribution of the angular orbital component shows the possibility of perpendicular magnetic anisotropy
