Perpendicular magnetic anisotropy of PdCo and PtCo based multilayers

Noble metal (Pt, Pd, Cu)/PdCo and Pt/PtCo multilayers were prepared by the RF sputtering method. Effective perpendicular anisotropy was measured by the torque method. It was found that Pd/PdCo and Pt/PdCo multilayers have positive surface anisotropy (K_s), while Cu/PdCo has a negative one. The origin of K_s was inferred to be a magnetoelastic energy of the PdCo layer which results from the lattice misfit between the noble metal and PdCo layers. In Pt/PtCo multilayers, K_s is much smaller than in Pt/PdCo and Pd/PdCo, indicating the absence of magnetoelastic surface anisotropy in PtCo-based multilayers