Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.18: Poster
Freitag, 4. April 2014, 10:30–13:30, P2
Thermal spin transfer torque in vortex state structures — •Michael Vogel1, Ajay Gangwar1, Susanne Brunner1, Stefan Günther1, Jean-Yves Chauleau1, Claudia Mewes2, Tim Mewes2, Georg Woltersdorf3, and Christian Back1 — 1U Regensburg, Regensburg, Germany — 2U Alabama, Tuscaloosa, USA — 3MLU Halle, Halle, Germany
It has recently been proposed that temperature gradients in magnetic structures can induce a thermal spin transfer torque (thermally induced STT) [J.C. Slonczewski, Phys. Rev. B 82, 054403 (2010)].
We study thermally induced spin-currents in lateral devices. In particular we will address the motion of a magnetic vortex core in a ferromagnetic square in the Landau state when subjected to a temperature gradient. We have modified our open source micromagnetic simulation package (M3) to include thermal spin transfer torque as suggested in [K.M.D. Hals, A. Brataas, and G.E.W. Bauer, Solid State Communications 150, 461-465 (2010)]. To test this simulator we compare the magnetization dynamics induced in a nanometer sized Permalloy square subjected to voltage driven STT [M. Najafi, et al., J. Appl. Phys. 105, 113914 (2009)] and thermally driven STT. We have also studied the dependence of the vortex motion as a function of the applied temperature gradient and the size of the Permalloy sample. The motion of the core can be compared to analytic approximations [B. Krüger, et al., Phys. Rev. B 76, 224426 (2007)] Further we have investigated the behavior of such vortex cores at the MAXYMUS scanning transmission X-ray microscopy (STXM) beam line at Bessy, Berlin.