  We report nonlocal spin injection and detection experiments on mesoscopic
Co-Al2O3-Cu spin valves. We have observed a temperature dependent asymmetry in
the nonlocal resistance between parallel and antiparallel configurations of the
magnetic injector and detector. This strongly supports the existence of a
nonequilibrium resistance that depends on the relative orientation of the
detector magnetization and the nonequilibrium magnetization in the normal metal
providing evidence for increasing interface spin scattering with temperature.
