On a simple derivation of the very low damping escape rate for classical spins by modifying the method of Kramers
| Autor: | Byrne, Declan J., Coffey, William T., Kalmykov, Yuri P., Titov, Serguey V. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Physica A, Volume 527, 121195 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.physa.2019.121195 |
| Popis: | The original perturbative Kramers' method (starting from the phase space coordinates) (Kramers, 1940) of determining the energy-controlled-diffusion equation for Newtonian particles with separable and additive Hamiltonians is generalized to yield the energy-controlled diffusion equation and thus the very low damping (VLD) escape rate including spin-transfer torque for classical giant magnetic spins with two degrees of freedom. These have dynamics governed by the magnetic Langevin and Fokker-Planck equations and thus are generally based on non-separable and non-additive Hamiltonians. The derivation of the VLD escape rate directly from the (magnetic) Fokker-Planck equation for the surface distribution of magnetization orientations in the configuration space of the polar and azimuthal angles $(\vartheta, \varphi)$ is much simpler than those previously used. Comment: 16 pages, 1 figure. Published in: Physica A: Statistical Mechanics and its Applications. Journal reference: Physica A, volume 527, 121195. Date of Publication: 1 August 2019. Publisher: Elsevier |
| Databáze: | arXiv |
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