Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.68: Poster

Friday, March 26, 2010, 11:00–14:00, Poster B1

Spin-transfer torque in MgO based tunnel junctions for different magnetic materials — •Christian Franz and Christian Heiliger — I. Physikalisches Institut, Justus Liebig University Giessen, D-35392, Germany

We use the non-equilibrium Keldysh formalism implemented in the Korringa-Kohn-Rostoker Green’s function method [1] to calculate the spin-transfer torque in MgO based tunnel junctions. In particular, we discuss the bias voltage dependence of the torque for different magnetic materials. We investigate Fe, Co, and FeCo leads. For pure Fe leads our calculations of the spin-transfer torque [2] show excellent quantitative agreement with experimental observation. Furthermore, our results show the importance of the Δ₁ band gap in the ferromagnetic materials. There is a drastic change in the bias dependence of the spin-transfer torque if the applied bias voltage is larger than the Δ₁ band gap.

[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).