ELECTRON LOCALIZATION IN CO NI SUPERLATTICES

The residual resistivity in Co/Ni superlattices is shown to oscillate as a function of superlattice period for fixed Co to Ni thickness rati o. Additional experimental evidence shows that this behavior is enhanc ed when randomness is artificially introduced in the individual layer thickness. We analyze this in terms of a scattering mechanism associat ed with the presence of localized electron eigenstates near the Fermi level in the metallic superlattices. A one-dimensional tight-binding c alculation shows that localized states appear close to superlattice pe riods for which the resistivity exhibits maxima.