Magnetic anisotropy and magneto-optical Kerr effect of Co/Pd_{1_x}Au_x metallic multilayers

We prepared Co/Pd_1-xAu_x multilayers on glass substrates by RF magnetron sputtering at room temperature. Co/Pd_{1_x}Au_x multilayers exhibit a magnetic easy axis perpendicular to the film plane up to a larger magnetic layer thickness than do Co/Pd multilayers. In particular, Co/Pd_o.7oAu_o.3o multilayers became perpendicular at 33 Å. The magnetic anisotropy can be explained by the strain effect. The role of the magnetoelastic energy due to the in-plane strain in the system is pointed out and discussed. We also investigated the magnetooptical polar Kerr effect of these multilayers. The polar Kerr rotation angle θ_k increases when the Au concentration is 4.5 at.% compared to Co/Pd multilayers but decreases with increasing Au content.