Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)
O 36.84: Poster
Dienstag, 15. März 2011, 18:30–22:00, P4
Standing-wave excited hard x-ray phototemission studies on a Au-sandwiched Fe/MgO interface — Sven Döring1, •Christoph Keutner1, Frank Schönbohm1, Ulf Berges1, Daniel E. Bürgler2, Mihaela Gorgoi3, Franz Schäfers3, Claus M. Schneider2, and Carsten Westphal1 — 1DELTA/Experimentelle Physik I, TU Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund — 2IFF-9, Forschungszentrum Jülich, 52425 Jülich — 3Helmholtzzentrum Berlin für Materialien und Energie, Albert Einstein Str. 15, 12489 Berlin
Magnetic tunnel junctions (MTJs) consisting of a thin layer-stack of Fe/MgO/Fe show a high tunnel-magneto resistance (TMR) ratio at room temperature. The strength of this effect is mainly driven by the interface and thus the Fe/MgO interface has been subject of many studies during the last years. Quite recently, calculations predicted an even higher TMR ratio for modified interfaces [1]. In that work it was proposed that a monolayer of Au at the interface prevents the oxidation of the Fe-layer, and thus an increase of the TMR effect is expected. Up to now there is no experimental evidence that a well-defined Au monolayer can be prepared with the objective of preventing the Fe oxidation at the interface. In this work we studied a Au-modified interface with standing-wave excited hard x-ray photoemission. The goal of this study was the determination of the effective roughness of the Au layer. Our data-analysis shows that Au does not grow as a protective monolayer nor any hint of FeO formation was found.
[1] J. Mathon and A. Umerski, Phys. Rev. B 71, 220402 (2005)