Structural effect of junction interface on magnetic properties in a Co/MgO/Co system: First-principles calculations

Abstract

The structural and magnetic properties of Co(001)/MgO(001)/Co(001) magnetic tunnel junctions with two types of junction interface, on an O-site adsorption case (Case I) and on a Mg-O twofold hollow site adsorption case (Case II), were investigated using density functional theory. Interfacial spin polarization values of electrodes were calculated to be -81.3% for Case I and -90.5% for Case II, resulting from the adsorption site dependency of electrode atoms on the MgO(001) surface. Interestingly, Mg and O atoms also showed significantly induced spin polarization values due to the 2p-3d hybridization between the Mg/O and Co-interface atoms. The magnetic moments of the electrode atoms were calculated to be 1.67 mu(B) and 1.72 mu(B) on average without significant variation across the electrode, except for the surface layer.