Comparison of magnetic properties of ultrathin Co/Si(111) and Co/Ag/Si(111) films

Abstract The thermal stability of the magnetization of the Co/Ag/Si(1 1 1) film is lower than that of the Co/Si(1 1 1) film. From Auger electron spectroscopy, we demonstrate that Ag atoms in the Co/Ag/Si(1 1 1) film segregate to top layers below 350 K. The segregation of Ag atoms improves the diffusion of Co into Si(1 1 1) substrate. Annealing 10.5 ML Co/Si(1 1 1) film causes the easy axis of magnetization to transform from an in-plane to a cant out-of-plane. The in-plane magnetization of 10.5 ML in Co/Ag/Si(1 1 1) film persists after annealing.