Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 103: Transport: Poster Session

TT 103.17: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster B

Effect of geometrical Langevin forces on magnetic dynamics — •Tim Ludwig¹ and Alexander Shnirman^1,2 — ¹Institut für Theorie der Kondensierten Materie, Karlsruher Institut für Technologie, Karlsruhe, Germany — ²DFG-Center for Functional Nanostructures (CFN), Karlsruher Institut für Technologie, Karlsruhe, Germany

Stochastic Landau-Lifshitz-Gilbert (LLG) equations with Langevin forces are a standard tool to describe the magnetic dynamics of ferromagnetic single-domain particles. In the classical regime, i.e. for temperatures much higher than the precession frequency, the results of Brown [1] can be used. Recently, it was predicted that, at low temperatures, the Langevin forces are influenced by the geometrical phases [2]. We analyzed the LLG-type Langevin equations with the geometrical Langevin forces for the situation of ferromagnetic resonance. At low temperatures, we found that the stationary distribution of the magnetization is governed by an effective geometric temperature rather than by the bath temperature.

[1] W. F. Brown, Phys. Rev. 130, 1677 (1963).

[2] A. Shnirman, Y. Gefen, A. Saha, I. S. Burmistrov, M. N. Kiselev,

and A. Altland, arXiv:1409.0150v1.