Perpendicular-current transport in exchange-biased spin-valves

We have measured giant magnetoresistance (GMR) with current perpendicular 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. Interpreted with the theory of Valet and Fert, the data yield an unexpectedly short value for the length over which electrons lose spin-memory in Py, the spin-diffusion length, l/sub sf//sup Py/=5.5/spl plusmn/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.