On the basis of He-ion backscattering, x-ray fluorescence, and complementary measurements, it is unambiguously established for the first time that the oxide layer on the surface of oxidized 81% Ni-19% Fe evaporated films is predominantly Fe-oxide. Extrapolation of results for pure iron films indicates that the oxide is most likely antiferromagnetic alpha-Fe2O3. On the basis of ferromagnetic resonance measurements, it is concluded that the oxide negligibly affects the pinning of the bulk spins at the film-oxide interface
