Quantum size effects and magnetoresistance in spin-valved Co/Cu/Co trilayer structures

Electron transport and the magnetoresistance of magnetron sputtered ultrathin Co(M-1)/Cu/Co(M-2) trilayer structures that are of comparable structural perfection are presented as a function of magnetic and nonmagnetic layer thicknesses. We apply the quantum well states model to the interpretation of the electron transport data, while also considering the shunting effects or classic diffuse bulk scattering effect on electron transport in these metallic trilayer structures. This approach represents a beyond free-electron approximation that takes into model calculations details of the electronic band structure of the trilayers and spin-dependent electron scattering by impurities and/or at interfaces. A concurrent description of both the resistivity and magnetoresistance data can be achieved, as distinguished from such general semiclassical ones as Camley-Barnas's and its deviations that account for the magnetoresistance well, but fail to describe electron transport of these layered structures in the ultrathin layer thickness limit. (C) 1999 American Institute of Physics. [S0021-8979(99)10803-X].