Inverse giant magnetoresistance in Fe/Cu/Co/Cu multilayers

摘要

We report on ab initio calculations of giant magnetoresistance in Fe/Cu/Co/Cu multilayers. The system is of special interest because its giant magnetoresistance switches from positive to negative values depending on the Fe layer thickness for current perpendicular-to-plane geometry. the electronic structure of systems under consideration is calculated within the frame of density functional theory using local spin density approximation. We assume scattering at impurities in the ferromagnetic layers, especially V impurities in the Fe layers and Cu impurities in Co layers or magnetic Co impurities in Cu layers. The scattering of the electorns by impurities is described self-consistently by means of the Green function of the perturbed system. As a result, the spin anisotropy of the scattering can be discussed free of any parameters. Transport is described quasi-classically. The Boltzmann equation is solved in relaxation time approximation taking into account the anisotropy of the Fermi surface of the layered system and the spin anisotropy of scattering.