Regensburg 2010 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 6: Poster Session I

DY 6.32: Poster

Montag, 22. März 2010, 16:00–18:00, Poster B2

Noise Effects in Ferromagnetic Systems — •Thomas Bose and Steffen Trimper — Martin-Luther-University, Halle, Germany

We study a model for ferromagnetic materials describing the propagation of spin waves under the influence of deterministic and stochastic forces. The analysis is performed referring to the classical limit by introducing a stochastic Landau-Lifshitz-Gilbert equation (LLG). The stochastic force has a finite correlation time τ leading to a non-Markovian process. The LLG is transformed into an equivalent equation for the corresponding probability distribution. Approximate equations for the mean values and the correlation functions, respectively, are derived. In general, the Gilbert damping leads to a decay of the spin wave amplitude. Whereas, this situation can change when both the deterministic and the stochastic forces act simultaneously on the system. In this case we found a phase diagram in terms of the Gilbert damping parameter α, the correlation strength of the random noises D and the correlation time τ.