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Published online by Cambridge University Press: 26 February 2011
Recent experiments have tested the assumption that a spin-dependent asymmetry in scattering is responsible for the giant magnetoresistance (GMR) in Fe/Cr multilayers by introducing additional impurities (with different spin-dependent scattering asymmetries) at the interfaces. This paper presents a theoretical calculation based on a Boltzmann transport equation approach which is appropriate for these new experiments. We find that when impurities (Mn, V) are introduced which have a spin-dependent scattering asymmetry similar to that of Cr in Fe the GMR is not substantially changed. When impurities (Al, Ir) with a spin-dependent scattering asymmetry opposite to that of Cr in Fe are introduced there is a rapid degredation of the GMR. Our results are compared with experiment and good agreement is found provided that the magnitude of the scattering asymmetry in Al is reduced somewhat from low-temperature published values. It is argued that thermal effects could indeed provide such a reduction. We also point out that the thermal conductivity should undergo changes with magnetic field in these structures, since the thermal conductivity also depends upon electron mobility.