ROLE OF INTERFACIAL MIXING IN GIANT MAGNETORESISTANCE

We show that the giant magnetoresistance in sputtered Ni-Fe/Cu/Ni-Fe/F e-Mn spin-valve structures is strongly reduced by the presence of comp ositionally intermixed regions at the NiFe/Cu interfaces. The ultrathi n intermixed layers, which are not ferromagnetic, are centers of stron g spin-independent scattering, thus reducing the flow of polarized ele ctrons from one ferromagnetic layer to the other. Our results show tha t interfacial spin-independent scattering must be included in the theo ry of giant magnetoresistance.