Specific resistance, scattering asymmetry, and some thermal instability, of Co/Al, Fe/Al, and [Co.sub.91][Fe.sub.9]/Al interfaces

From measurements of the Current-Perpendicular-to-Plane (CPP) resistances and magnetoresistances (MRs) of sputtered [[F/Al].sub.N] (F= Co, Fe, [Co.sub.91][Fe.sub.9]) multilayers with N-bilayers, and F/Al-based exchange-biased spin-valves, we estimate interface specific resistances, 2A[R*.sub.F/Al], and scattering asymmetries, [[gamma].sub.F/Al], for each metal pair at 4.2 K. In all three cases, 2A[R*.sub.F/A1] is large and [[gamma].sub.F/Al] is small, comparable to the recently determined values of 2A[R*.sub.Py/Al] ~ 9 f[OMEGA][m.sup.2] and [[gamma].sub.Py/Al] ~ 0.03 for Permalloy (Py)/Al interfaces. The values of 2A[R*.sub.F/Al] with Al are too large to be explained by the resistivities of alloyed F/Al interfaces. The similarity of results for Py, Fe, Co, and [Co.sub.91] [Fe.sub.9] suggests that spin dependent scattering at F/Al interfaces is determined mainly by the properties of Al. We find that F/Al interfaces are not stable over time at 295 K or upon annealing to 450 K. Index Terms--Current perpendicular-to-plane (CPP) magnetoresistance (MR), interface resistance, interface scattering asymmetry.