Spin-flipping at Sputtered Co/Ag Interfaces

We measured at 4.2K the Current-Perpendicular-to-Plane Magnetoresistances (CPP-MRs) of sputtered ferromagnetically coupled [Co(3 nm)/Ag(1.8 or 2.0 nm)]$_{n}$Co(3 nm) multilayers with $n$ = 0 to 8 that were imbedded in the middle of symmetric, Py-based, double exchange-biased spin-valves. The measurements yielded the parameter for spin-flipping at the Co/Ag interface, $\delta _{Co/Ag}=\mathop {0.30}\nolimits_{-0.1}^{+0.05} $. $\delta $ is related to the probability $P$ of spin-flipping at the Co/Ag interface by $P$ = [(1-exp(-$\delta )$]. Despite the expected larger lattice-mismatch-induced disorder at the Co/Ag interface, this value is similar to that reported earlier for the Co/Cu interface [1], suggesting that such disorder does not play a major role in $\delta _{F/N}$ at ferromagnetic/non-magnetic (F/N) interfaces. \\[4pt] [1] B. Dassonneville et al., Appl. Phys. Lett. 96, 022509 (2010).