Changes in magnetic scattering anisotropy at a ferromagnetic/superconducting interface

We show that some metals and alloys (Cu, Ag, FeMn, or Cu and Ag combined with each other), sputtered between ferromagnetic Co and superconducting Nb, produce no change in current-perpendicular-to-plane (CPP) magnetoresistance (MR) in a carefully designed CPP spin valve. In contrast, other metals (Ru or Au) or combinations (Cu or Ag combined with Au, Ru, or FeMn) change the CPP-MR, in some cases even reversing its sign. We ascribe the latter changes to activation of magnetic scattering anisotropies at a ferromagnetic/superconducting interface, with the differences in behavior for different metals apparently driven by differences in the strength of spin flipping when these metals are inserted between the Co and Nb layers.