Surface oxidation as a diffusion barrier for Al deposited on ferromagneticmetals

Grazing incidence x-ray reflectometry has been used to study surface oxidat ion as a diffusion barrier for Al deposited on ferromagnetic metals (Co, Fe , Ni, and Ni80Fe20). Samples of the form SiO2\ 10 nm X \4 nm Al with X =(Co , Fe, Ni, and Ni80Fe20) were investigated for X \ Al intermixing. Surface o xidation was achieved by exposing the ferromagnetic layer to O-2 to oxidize the top two or three atomic layers before depositing the Al layer. Specula r x-ray scans were used for the analysis. Samples of the form SiO2\ 10 nm X \4 nm Au were used to separate topographical roughness from intermixing. S urface oxidation was found to suppress the diffusion of Al into Co, Ni, and Ni80Fe20 but not into Fe. (C) 2001 American Institute of Physics.