Towards a Unified Picture of Spin Dependent Transport in and Perpendicular Giant Magnetoresistance and Bulk Alloys

From data on $({\mathrm{Fe}}_{1-x}{\mathrm{V}}_x/\mathrm{Cu}/\mathrm{Co}/\mathrm{Cu}{)}_N$ multilayers, we show that Fe doped with V gains a negative spin asymmetry for bulk scattering $(\beta <0\mathrm{})$, which, combined with the positive asymmetry of Co, accounts for the inverse current perpendicular to the plane (CPP) giant magnetoresistance (GMR) we observe. More precisely, the competition between positive and negative asymmetries for interface and bulk scatterings in FeV leads to inverse (normal) GMR for layers thicker (thinner) than a compensation thickness. The negative $\beta$ of FeV is consistent with theoretical predictions and bulk alloy data. The current in the plane (CIP) GMR is not reversed, which illustrates the role of channeling in CIP.