Regensburg 2002 – wissenschaftliches Programm

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MA: Magnetismus

MA 7: Spinabhängige Transportphänomene II

MA 7.4: Vortrag

Dienstag, 12. März 2002, 10:15–10:30, H22

Electronic, magnetic, and tunneling properties of Fe/MgO/Fe planar junctions — •Mohammed Bouhassoune, Arthur Ernst, Jürgen Henk, and Patrick Bruno — MPI für Mikrostrukturphysik, Halle (Saale)

The tunneling magneto-resistance (TMR) of Fe/MgO/Fe planar junctions depends strongly on the geometrical and magnetic properties of the Fe/MgO interfaces. Hence, to obtain reliable theoretical TMR results one has to describe correctly the latter.

Ab-initio screened-KKR calculations within the local spin-density approximation of the density-functional theory provided the electronic and magnetic structure of epitaxial Fe(100)/MgO(100)/Fe(100) junctions. The geometrical structure used was determined recently by surface x-ray diffraction [1]. In that experiment, an FeO oxide layer was found at the Fe/MgO interface which has not been considered in previous theoretical work [2]. To treat properly the strongly localized 3d-electrons in this layer, we applied the self-interaction correction (SIC).

Results of the electronic and magnetic properties are presented for systems with several MgO-spacer thicknesses. In particular, we focus on the spin-dependent tunneling as described within the layer-KKR formulation of the Landauer-Büttiker theory.

[1] H. L. Meyerheim, R. Popescu, J. Kirschner, N. Jedrecy, M. Sauvage-Simkin, B. Heinrich, and R. Pinchaux, Phys. Rev. Lett. 87 (2001) 076102.

[2] W. H. Butler, X.-G. Zhang T. C. Schulthess, and J. M. MacLaren, Phys. Rev. B 63 (2001) 054416; J. Mathon and A. Umerski, Phys. Rev. B 63 (2001) 220403.