Interface magnetic anisotropy for monatomic layer-controlled Co/Ni epitaxial multilayers

The magnetic properties for monatomic layer (ML)-controlled Co/Ni epitaxial multilayers were investigated in order to evaluate the interface magnetic anisotropy energy (K_s) between Ni and Co layers. The Co/Ni epitaxial multilayers were prepared on an Al₂O₃ (11-20) substrate with V/Au buffer layers. The value of K_s was definitely larger than that for the textured Co/Ni grown on a thermally oxidized Si substrate. We consider that the sharp interface for the epitaxial Co/Ni played a role to increase the value of K_s, which also enabled us to obtain perpendicular magnetization even for the 1 ML-Co/1 ML-Ni multilayer.