OBSERVATION OF SPIN-POLARIZATION EFFECTS IN DISORDERED METALS

We have studied the properties of submicrometer thin-film Au conductors that are in direct contact with relatively thick films of Fe. The magnetoresistance of these structures exhibits features that appear to be due to spin polarization of the conduction electrons in the Au, which is induced through their proximity to the Fe. The results imply that the length scale over which electrons maintain a "memory" of this polarization is of order 1-mu-m at a temperature of 4 K. This is much longer than both the elastic mean free path and the spin-orbit scattering length, but is of the order of the electron-phase-coherence length. Our results are in accord with recent theories.