Regensburg 2010 – scientific programme

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DS: Fachverband Dünne Schichten

DS 29: Poster: Molecular Spintronics, Biomolecular and Functional Organic Layers, Organic Electronics and Photovoltaics, Plasmonics and Nanophotonics, Organic Thin Films, Nanoengineered Thin Films, Thin Film Characterisation,

DS 29.46: Poster

Wednesday, March 24, 2010, 15:00–17:30, Poster A

Structure analysis of CoFeB/MgO interfaces by focus series reconstruction — •Henning Schuhmann¹, Patrick Peretzki¹, Gerrit Eilers², Michael Seibt¹, Markus Münzenberg², Volker Drewello³, Andy Thomas³, and Günter Reiss³ — ¹IV. Physikalisches Institut, Georg-August-Universität Göttingen, Germany — ²I. Physikalisches Institut, Georg-August-Universität Göttingen, Germany — ³Thin films and Physics of Nanostructures, Universität Bielefeld, Germany

The amorphous CoFeB/ crystalline MgO interface is a fundamental part of magnetic tunnel junctions (MTJ) which are a potential candidate for magnetic random access memory. For these applications a high tunnel magnetoresistance (TMR) is required. Ab initio supercell calculations by Heiliger et al. [1] show, that the TMR increases rapidly with the number of crystalline Fe monolayers at the interface.

These predictions are to be compared with quantitative analysis by high resolution transmission electron microscopy (HRTEM). The cross-section TEM specimens were prepared by Focused Ion Beam (FIB) and conventional techniques.

Using object wave reconstruction from defocus series, local long-range order at these interfaces is investigated. Combined with electrical characterization of TMR devices the correlation of interfacial order and TMR values is investigated.

[1] Ch. Heiliger, M. Gradhand, P. Zahn and I. Mertig, Phys. Rev. Lett. 99, 066804 (2007)