Perpendicular giant magnetoresistance of Co91Fe9/Cu exchange-biased spin-valves: further evidence for a unified picture

Measurements are reported of the increase in specific resistance, A Delta R , with increasing Co91Fe9 layer thickness in current-perpendicular to the p lane (CPP) exchange-biased spin-valves (EBSVs) of Co91Fe9 and Cu. Analysis of these measurements yields a spin anisotropy parameter for Co91Fe9 of bet a = 0.65 +/- 0.05, and a spin diffusion length of l(sf)(CoFe) = 12 +/- 1 nm . The value of beta agrees reasonably well with those obtained experimental ly and theoretically for dilute CoFe alloys, thus providing additional supp ort for a unified picture of spin-polarized transport in CPP-MR and bulk al loys. This value of l(sf)(CoFe), and the previously determined l(sf)(Py) fo r Permalloy, scale approximately inversely with the residual resistivities of the two alloys. (C) 1999 Elsevier Science B.V. All rights reserved.