The influence of spin-independent disorder on giant magnetoresistance

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Abstract
We demonstrate that the giant magnetoresistance (GMR) effect in magnetic multilayers can be explained quantitatively in terms of the scattering of electrons from a spin-independent random potential that arises from the grown-in defects within the multilayer. We have calculated the GMR ratio for Co/Cu and Fe/Cr multilayered systems within the Kubo - Greenwood formalism assuming that the on-site atomic energies are disordered randomly within a realistic spd tight-binding model. Our predictions are in good agreement with experiment and demonstrate how the GMR ratio depends on the features of the electronic band structure. In particular, we obtain the enhancement of GMR in Co/Cu multilayers at electron energies up to about 1 eV above the Fermi level that has recently been observed by Monsma et al [1995 Phys. Rev. Lett. 74 5260]. We predict no such enhancement for Fe/Cr multilayers.