Giant magnetoresistance of current-perpendicular exchange-biased spin-valves of Co/Cu

We present the first measurements of the specific resistance change, A/spl Delta/R, with increasing Co layer thickness, t/sub Co/, of current-perpendicular (CPP) exchange biased spin-valves (EBSVs) of Co and Cu. A/spl Delta/R grows about as predicted for a long spin diffusion length in Co until about t/sub Co/=20 nm, after which it grows more slowly than predicted. Possible reasons for this deviation from prediction are considered, including a short spin diffusion length in Co.