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O: Fachverband Oberflächenphysik

O 32: Surface or interface magnetism

O 32.3: Vortrag

Mittwoch, 25. März 2009, 11:00–11:15, SCH A315

Depth-resolved photoemission studies on the system MgO/Fe — •Sven Döring^{1, 2}, Frank Schönbohm^{1, 2}, Ulf Berges^{1, 2}, See-Hun Yang³, Christian Papp^{3, 4}, Benjamin Balke^{3, 4}, Reinert Schreiber⁵, Daniel E. Bürgler⁵, Claus M. Schneider⁵, Charles S. Fadley^{3, 4}, and Carsten Westphal^{1, 2} — ¹DELTA, TU Dortmund, Maria-Goeppert-Mayer-Str. 2, 44221 Dortmund, Germany — ²Experimentelle Physik 1, TU Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund, Germany — ³Materials and Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA — ⁴University of California, Davis, CA 95616, USA — ⁵Jülich Forschungszentrum, IFF-9, 52425 Jülich, Germany

A high depth-resolution in photoemission experiments can be obtained by exciting the photoemission process with nm-scale x-ray standing waves above a multilayer mirror (e.g. Yang et al., J. Appl. Phys. 103, 07C519 (2008)). With this technique, we investigated a model MgO/Fe magnetic tunnel junction, in particular exploring the degree of Fe oxidation at the interface between the two layers, which is thought to critically affect the tunnel magnetoresistance.. With the Fe in a wedge profile, the MgO-Fe interface can be moved through the standing wave field by moving the sample relative to the beam. The experiments were performed at DELTA (Dortmund), the ALS (Berkeley), and BESSY II (Berlin). Such standing wave/wedge scans, as well as rocking curves, allow us to develop a depth-profile of our sample. As one preliminary conclusion, we find no evidence for the presence of iron oxide at the interface.