Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 3: Spin-Dependent Transport Phenomena I
MA 3.3: Vortrag
Montag, 27. März 2006, 10:45–11:00, HSZ 103
Ab initio calculations of spin-dependent tunneling conductance in Fe/FeCo/MgO/Fe: Role of the interfaces — •Daniel Wortmann1, Jussi Enkovaara1,2, and Stefan Blügel1 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, Germany — 2CSC – Scientific Computing,Espoo, Finland
Magnetic tunneljunctions based on epitaxially grown MgO are currently the most promising system for magnetoelectonic applications like magnetic random access memory cells. Record high tunneling magneto-resistance values at room temperature have been achieved in such junctions [1]. We will present ab initio calculations of electron tunneling in Fe/MgO based tunneljunctions with the focus on the details of the interface structure and its influence on the tunneling conductance. In particular we will show the differences which can be expected between a pure Fe/MgO/Fe junction and a Fe/Co/MgO/Fe system in which one or two monolayers of Co have been added at the interface as well as a Fe/FeCo/MgO/Fe junction in which a two-dimensional FeCo alloy is present at the interface. The calculations are carried out within the density-functional theory with the full-potential linearized augmented plane wave (FLAPW) method. The novel embedded Green function method enables us to treat semi-infinite junctions and to calculate the spin-dependent conductance[2].
[1] S. Yuasa et al., Nature Materials 3, 868 (2004); and S. Parkin et al., ibid, 862 (2004)
[2] D. Wortmann, H. Ishida, and S. Blügel, Phys. Rev. B 65, 165103 (2002); ibid 66, 075113 (2002)