Effects of annealing and ion implantation on the magnetic properties of Pd/Co multilayers containing ultrathin Co

Polycrystalline Pd/Co multilayers containing Co layers in the monolayer regime and having perpendicular magnetic anisotropy were subjected to diffusion anneals up to 400°C and to 600 keV Kr+ bombardment. As a result of Pd-Co mixing these treatments led to a decrease of the perpendicular anisotropy, coercivity and remanence. Diffusion was studied quantitatively by means of X-ray diffraction. The results indicate that diffusion occurs primarily along grain boundaries, which initially are migrating and finally become stationary. In this latter stage the activation energy of diffusion is 1.1 eV.