We have measured Giant Magnetoresistance (GMR) with Current Perpendicu
lar to the layer Planes (CPP-MR) in Exchange-Biased (EB) spin-valves-a
controllable spin-switch. We will present CPP data on EB-spin-valves
of Permalloy (Py) and Cu, and explain how the data are analyzed. Inter
preted with the theory of Valet and Fert, the data yield an unexpected
ly short value for the length over which electrons lose spin-memory in
Py, the spin-diffusion length, l(sf)(Py) = 5.5 +/- 1 nm. We will show
that the CPP parameters derived with the aid of single EB-spin-valves
predict rather well the CPP-MRs of double EB-spin-valves.