Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 13: Spinabh
ängiger Transport I

MA 13.7: Vortrag

Samstag, 5. März 2005, 12:15–12:30, TU EMH225

Tunneling in Fe/MgO/Fe: Influence of interface structure and bias voltage — •Christian Heiliger, Bogdan Yu. Yavorsky, Peter Zahn, and Ingrid Mertig — Martin-Luther-University Halle-Wittenberg, Department of Physics, Von-Seckendorff-Platz 1, 06120 Halle, Germany

Newest experimental results of Fe/MgO/Fe tunnel junctions [1] show a strong dependence of the tunnel magnetoresistance on the sample and in particular the interface quality. An elaborate experimental analysis of the interface composition in Fe/MgO/Fe tunnel junctions reveals the formation of a mixed Fe/O layer [2]. To elucidate their influence on conductance and tunneling magnetoresistance (TMR) electronic structure calculations have been performed. A screened Korringa-Kohn-Rostoker (KKR) method based on density-functional theory was applied. The Landauer conductance of planar junctions was calculated using the Baranger-Stone scheme by means of Green functions. The influence of structural relaxation, formation of a mixed Fe/O-layer and the finite bias voltage on conductance and TMR are discussed.

[1] S. Yuasa, T. Nagahama, A. Fukushima, Y. Suzuki and K. Ando, Nature mat. AOP (31 October 2004); doi: 10.1038/nmat1257

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