  Using combined magnetometry and ferromagnetic resonance studies, it is shown
that introduction of a hydrocarbon cover layer leads to an increase of the
contribution of the surface anisotropy to the effective magnetic anisotropy
energy of hexagonal close-packed 0001 cobalt films, largely enhancing the
perpendicular anisotropy. Due to a weak electronic interaction of the organic
molecules with the Co atoms, an increase of surface anisotropy could be
explained by the presence of an electric field at the organic-material/Co
interface and by modification of surface atoms charge configuration.
