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MA: Fachverband Magnetismus

MA 27: Spintronics (incl. Quantum Dynamics)

MA 27.4: Vortrag

Dienstag, 21. März 2017, 14:45–15:00, HSZ 301

Spin-torque Effects in Thermally Assisted Magnetization Reversal: Kramers' Escape Rate Theory Approach — Yuri P. Kalmykov¹, Declan J. Byrne², •William T. Coffey³, William J. Dowling³, Sergey V. Titov⁴, and Jean Eric Wegrowe⁵ — ¹Univ. Perpignan Via Domitia, Laboratoire de Mathématiques et Physique, F-66860, Perpignan, France — ²School of Physics, University College Dublin, Belfield, Dublin 4, Ireland — ³Department of Electronic and Electrical Engineering, Trinity College, Dublin 2, Ireland — ⁴Kotel'nikov Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, Vvedenskii Square 1, Fryazino, Moscow Region, 141120, Russia — ⁵Laboratoire des Solides Irradiés, Ecole Polytechnique, 91128 Palaiseau Cedex, France

Thermal fluctuations of nanomagnets driven by spin-polarized currents are treated via the Landau-Lifshitz-Gilbert equation generalized to include both the random thermal noise field and the Slonczewski spin-transfer torque (STT) term. The reversal time of the magnetization in such a nanomagnet are evaluated for wide ranges of damping by using the method of Coffey et al. [Phys. Rev. E 63, 021102 (2001)]. Their method generalizes the Mel'nikov-Meshkov approach [J. Chem. Phys. 85, 1018 (1986)] for bridging the very low damping (VLD) and intermediate damping (ID) Kramers escape rates for mechanical Brownian particles (the Kramers turnover problem) to the analogous magnetic turnover problem.