Print Email Facebook Twitter Spin-transfer torque in magnetic tunnel junctions: Scattering theory Title Spin-transfer torque in magnetic tunnel junctions: Scattering theory Author Xiao, J. Bauer, G.E.W. Brataas, A. Faculty Applied Sciences Department Kavli Institute of Nanoscience Date 2008-06-12 Abstract We study the bias-dependent spin-transfer torque in magnetic tunnel junctions in the Stoner model by scattering theory. We show that the in-plane (Slonczewski type) torque vanishes and subsequently reverses its direction when the bias voltage becomes larger or the barrier wider than material and device-dependent critical values. We are able to reproduce the magnitude and the bias dependence of measured in-plane and out-of-plane torques using realistic parameters. The condition for the vanishing torque is summarized by a phase diagram depending on the applied bias and barrier width, which is explained in terms of an interface spin polarization and the electron focusing by the barrier. Quantum size effects in the spin-transfer torque are predicted as a function of the thickness of a normal-metal layer inserted between the ferromagnet and tunnel barrier. Subject ferromagnetisminterface magnetismmagnetic transitionsmagnetic tunnellingsize effectspin polarised transport To reference this document use: http://resolver.tudelft.nl/uuid:3da5158a-0280-4362-8a32-bac9362be5b4 Publisher American Physical Society ISSN 0163-1829 Source Physical Review B, 77 (22), 2008 Part of collection Institutional Repository Document type journal article Rights (c) 2008 The Author(s) ; American Physical Society Files PDF Xiao_2008.pdf 252.31 KB Close viewer /islandora/object/uuid:3da5158a-0280-4362-8a32-bac9362be5b4/datastream/OBJ/view