Magnetocrystalline anisotropy of Co-Pd interfaces

The interface magnetocrystalline anisotropy (MCA) of a Pd/Co/Pd sandwich is calculated by employing the recently proposed state-tracking approach and the full-potential linearized augmented-plane-wave energy band structure. The strong positive (perpendicular) Co-Pd interface MCA arises from the hybridization between the out-of-plane Co bonding xz(yz) states with the interface Pd atom: the large d-d bonding strength and high energy of the Pd d states shifts a substantial component of these Co states (bands) above the Fermi energy. Comparisons with a previous study on the Co-Cu interface makes clear that the difference between the effects of two groups of substrates (Cu, Ag versus Pd, Au, etc.) depends on the interface bonding strength and the position of the d states of the interface atomsas is qualitatively revealed by an analysis based on the use of an effective-ligand-interaction model.