On the basis of the density-functional theory, we numerically calculated th
e interfacial magnetism of slab models including Al/Co and O/Co interfaces.
We obtained the local magnetic moments and spin polarizations for various
types of models. We found that the interfacial Al layers exhibit positive s
pin polarizaition in specific atomic arrangements, such as O/Al/Co. The sig
n is consistent with the experimental result of the ferromagnet/insulator/s
uperconductor junction. This result suggests that in the junction Co/Al2O3/
Co, the tunneling of s-character electrons in Al is favored to that of d-ch
aracter electrons in Co.