Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 27: Spinabh
ängiger Transport II
MA 27.9: Vortrag
Donnerstag, 11. März 2004, 17:15–17:30, H22
Spin-dependent tunneling in Fe/vacuum/Cr system — •Jussi Enkovaara1, Daniel Wortmann1,2, and Stefan Blügel1,3 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich — 2Research Institute for Computational Sciences, Tsukuba, Japan — 3Fachbereich Physik, Universität Osnabrück, 49069 Osnabrück
Advances in spin-polarized scanning tunneling microscopy (SP-STM) have enabled the imaging of surface magnetism in sub-nm scale. The use of an antiferromagnetic tip material (or coating) is one possibility for obtaining the atomic scale spin sensitivity without generating a magnetic stray field. In this work, we study spin-polarized tunneling theoretically in a simple model system. We consider planar junction where a semi-infinite ferromagnetic Fe is separated from a semi-infinite antiferromagnetic Cr by a vacuum barrier. We employ a first-principles Green function approach based on the full-potential linearized augmented plane wave (FLAPW) method as implemented in the FLEUR code. The semi-infinite structures are treated with an embedding method. The tunneling current is calculated both within the Landauer and Bardeen formalisms. The results are compared to those obtained from a simple density of states picture.