Inverse giant magnetoresistance due to spin-dependent interface scattering in Fe/Cr/Au/Co

We have found an inverse current-in-plane giant magnetoresistance (CIP-GMR) effect in epitaxial Fe/Cr/Au/Co samples grown by molecular-beam epitaxy. The Fe and Co magnetic layers are decoupled, and antiparallel alignment is achieved by the different coercivities of the Fe and Co layers. The inverse GMR ratio is approximately one order of magnitude smaller than i) the normal GMR ratio of Fe/Cr/Co or comparable epitaxial Fe/Cr/Fe samples, and ii) the simultaneously observed anisotropic magnetoresistance (AMR). The comparison with Fe/Cr/Co and Fe/Au/Co systems, which both show a normal GMR effect, demonstrates that the inversion of the GMR effect is solely induced by modifying the non-magnetic spacer layer. Therefore, these experiments give strong evidence that interface scattering significantly contributes to the CIP-GMR. This conclusion is further supported by an analysis in terms of interface scattering spin asymmetries.