Conduction electron scattering and spin flipping at sputtered Co/Ni interfaces

Current-perpendicular-to-plane magnetoresistance (CPP-MR) measurements let us quantify conduction electron scattering and spin flipping at a sputtered ferromagnetic/ferromagnetic (F1/F2=Co/Ni) interface, with important consequences for CPP-MR and spin-torque experiments with perpendicular anisotropy. We use ferromagnetically coupled [Ni/Co](n)Ni multilayers, and Py-based, symmetric double exchange-biased spin valves containing inserts of ferromagnetically coupled [Co/Ni](n)Co or [Ni/Co](n)Ni multilayers, to derive Co/Ni interface specific resistances AR(Co/Ni)(up arrow) = 0.03(-0.03)(+0.02) f Omega m(2) and AR(Co/Ni)(down arrow) = 1.00 +/- 0.07 f Omega m(2), and interface spin-flipping parameter delta(Co/Ni)=0.35 +/- 0.05. The specific resistances are consistent with our no-free-parameter calculations for an interface thickness between 2 and 4 monolayers that is compatible with expectations.