Combined impurity and band effects on the appearance of inverse giant magnetoresistance in Cu/Fe multilayers with Cr

J.MILANO; A.M. LLOIS; L.B. STEREN

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 2002 vol. 66 p. 134405 - 134412

1098-0121

We have studied the dependence of impurity vs band effects in the appearance of inverse giant magnetoresistance (IGMR) in Cu/Fe superlattices with Cr. Current in plane (CIP) and current perpendicular to the plane geometries are considered. For the calculation of the conductivities, we have used the linearized Boltzmann equation in the relaxation time approximation. Cr impurity effects are taken into account through the spin-dependent relaxation times and the band effects through the semiclassical velocities obtained from the local-density approximation calculated electronic structure. The larger the Cr/Fe hybridization strength, the bigger is the tendency towards IGMR. In particular, in CIP geometry roughness at these interfaces increases the IGMR range. The calculated giant magnetoresistance ratios have been compared with the experimental results. From this comparison we conclude that the experimental data can only be explained by taking into account Cr bands.