Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 7: Spin-Dynamics/ Spin-Torque II
MA 7.3: Vortrag
Montag, 23. März 2009, 15:45–16:00, HSZ 04
Influence of lead material on spin-transfer torque in MgO based tunnel junctions — •Christian Heiliger1, Asma H. Khalil1, and Mark D. Stiles2 — 1I. Physikalisches Institut, Justus Liebig University Giessen, D-35392, Germany — 2Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6202, USA
We report calculations of the spin-transfer torque in MgO based tunnel junctions using a non-equilibrium Keldysh formalism implemented in the Korringa-Kohn-Rostoker Green’s function method [1]. Our calculations for Fe/MgO/Fe tunnel junctions show excellent quantitative agreement of the voltage dependence with experimental observation [2]. In this talk we discuss the influence of other lead materials on the bias dependence of the spin-transfer torque. We show the importance of the Δ1 band gap in the ferromagnetic materials. In particular, the bias dependence of the spin-transfer torque is changed drastically if the applied bias voltage is larger than the Δ1 band gap. This work has been supported in part by the NIST-CNST/UMD-NanoCenter Cooperative Agreement.
[1] C. Heiliger, M. Czerner, B. Yu. Yavorsky, I. Mertig, M. D. Stiles, J. Appl. Phys. 103, 07A709 (2008)
[2] C. Heiliger and M.D. Stiles, Phys. Rev. Lett. 100, 186805 (2008)