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arXiv · 0711.4560

Ab initio studies of the spin-transfer torque in tunnel junctions

Christian Heiliger·M. D. Stiles
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Abstract

We calculate the spin-transfer torque in Fe/MgO/Fe tunnel junctions and compare the results to those for all-metallic junctions. We show that the spin-transfer torque is interfacial in the ferromagnetic layer to a greater degree than in all-metallic junctions. This result originates in the half metallic behavior of Fe for the $Δ_1$ states at the Brillouin zone center; in contrast to all-metallic structures, dephasing does not play an important role. We further show that it is possible to get a component of the torque that is out of the plane of the magnetizations and that is linear in the bias. However, observation of such a torque requires highly ideal samples. In samples with typical interfacial roughness, the torque is similar to that in all-metallic multilayers, although for different reasons.

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Christian Heiliger, M. D. Stiles. 2007-11-28. Ab initio studies of the spin-transfer torque in tunnel junctions. https://doi.org/10.1103/physrevlett.100.186805

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