Abstract
The influence of Mn impurities on the electric transport properties of Fe/Cr/Fe sandwiches has been investigated as a function of the thickness of the Cr layer by employing the Kubo–Greenwood equation. The electronic and magnetic properties of the Fe/Cr sandwich-structures have been evaluated within the screened Korringa–Kohn–Rostoker method for layered systems. In this article, two types of impurities are studied: atomic layers of Mn placed on top of the Cr layers, and spacers consisting of disordered CrMn alloys. In agreement with experimental findings it is found that the size of the giant magnetoresistance (GMR) is not much affected by Mn impurities. However, Mn is known to transform the spin density wave (SDW) of Cr into a commensurate antiferromagnetic structure. These kinds of changes in the magnetic coupling are reflected in the GMR. The present results show that 5% of Mn in the spacer is sufficient to destroy the SDW.
Acknowledgements
Support has been provided by the Deutsche Forschungsgemeinschaft through the SFB 491, by the RT-network Computational Magnetoelectronics, and by the Hungarian National Scientific Research Foundation (OTKA T038162 and OTKA T037856).