  From measurements of the current-perpendicular-to-plane (CPP)
magnetoresistance of ferromagnetically coupled [Co(90)Fe(10)/Cu]xn multilayers,
within sputtered Permalloy-based double exchange biased spin-valves, we
determine the parameter delta[(Co(90)Fe(10))/Cu] = 0.19 +/- 0.04 that sets the
probability P of spin-flipping at a Co(90)Fe(10)/Cu interface via the equation
P = 1 - exp(-delta).
