First-principles investigation of the very large perpendicular magnetic anisotropy at Fe vertical bar MgO and Co vertical bar MgO interfaces

Abstract

The perpendicular magnetic anisotropy (PMA) arising at the interface between ferromagnetic transition metals and metallic oxides was investigated via first-principles calculations. In this work very large values of PMA, up to 3 erg/cm(2), at Fe vertical bar MgO interfaces are reported, in agreement with recent experiments. The origin of PMA is attributed to overlap between O-p(z) and transition metal d(z2) orbitals hybridized with d(xz(yz)) orbitals with stronger spin-orbit coupling-induced splitting around the Fermi level for perpendicular magnetization orientation. Furthermore, it is shown that the PMA value weakens in the case of over- or underoxidation due to the fact that oxygen p(z) and transitionmetal d(z2) orbital overlap is strongly affected by disorder, in agreement with experimental observations in magnetic tunnel junctions.