Contribution of surface scattering to the GMR effect in the magnetic multilayer films

At room temperature, we examine the magnetotransport properties for two types of magnetic layered structures, namely spin valves and magnetic multilayers, which exhibit the effect of a giant magnetoresistance (GMR). The MR in [Co(4 Å)/Cu(5 Å)/Co(4 Å)] spin valve depends on outer surface scattering properties, and its behaviour differs by varying the interfacial geometric random roughness magnitude from 0.2 to 4 Å. The [Co(4 Å)/Cu(5 Å)]_n multilayers show an identical variation of their MR by increasing the layer pairs number. The magnetoresistive effect reaches its optimal value around 200% for n = 25 during a completely specular scattering by the external boundaries of a multilayer composed by smooth interfaces. We also find that specular scattering at the top outer boundary of the metallic sandwiches enhances their GMR effect during its evolution according to the top Co layer thickness.