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

Electron transport and the magnetoresistance of magnetron sputtered ultrath in 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 t hicknesses. We apply the quantum well states model to the interpretation of the electron transport data, while also considering the shunting effects o r classic diffuse bulk scattering effect on electron transport in these met allic 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 i mpurities and/or at interfaces. A concurrent description of both the resist ivity and magnetoresistance data can be achieved, as distinguished from suc h general semiclassical ones as Camley-Barnas's and its deviations that acc ount for the magnetoresistance well, but fail to describe electron transpor t of these layered structures in the ultrathin layer thickness limit. (C) 1 999 American Institute of Physics. [S0021-8979(99)10803-X].