Spin-torque Effects in Thermally Assisted Magnetization Reversal: Kramers' Escape Rate Theory Approach

Yuri Kalmykov (1) , Declan Byrne (2) , William Coffey (3) , William Dowling (3) , Sergey Titov (4) , Jean Eric Wegrowe (5)

1 LAMPS - LAboratoire de Modélisation Pluridisciplinaire et Simulations
2 Department of Electronic and Electrical Engineering [Dublin]
3 Trinity College Dublin
4 IRE - Kotelnikov Institute of Radio Engineering and Electronics
5 LSI - Laboratoire des Solides Irradiés - Irradiated Solids Laboratory

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.

Domaines: Physique [physics]

Yuri Kalmykov, Declan Byrne, William Coffey, William Dowling, Sergey Titov, et al.. Spin-torque Effects in Thermally Assisted Magnetization Reversal: Kramers' Escape Rate Theory Approach. Annual German Physical Society Spring Meeting: Magnetism Division, Mar 2017, Berlin, Germany. ⟨hal-01624663⟩