Unified picture of spin-dependent transport in GMR multilayered structures and bulk ferromagnetic alloys

We have observed a positive (inverse) CPP-MR in magnetic multilayers of the forms: (a) (XY/Cu/Co/Cu)_n with XY being the alloys FeCr, FeV, NiCr, CoCr, and (b) (Z/Cr/NiFe/Cr)_n with Z = Fe and Co. For (a) the inverted results arise primarily from spin-dependent scattering in the bulk of the alloy, and are linked consistently to: (1) their magnetization; (2) band-structure calculations and (3) resistivity of bulk alloys. For (b) samples, the inverse MRs arise primarily from the scattering at the Fe/Cr and Co/Cr interfaces. Inverse MR for X/Y interfaces and XY alloys (eg. Fe/Cr and FeCr) arises from the similarity of the matching problem of X and Y d levels at interfaces and in alloys. For all XY the CIP-MR was negative, confirming that CIP-MR is strongly influenced by channeling effect and current inhomogenieties.