Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.79: Poster

Freitag, 26. März 2010, 11:00–14:00, Poster B1

Magnetization dynamics control of a single ferromagnetic nanoparticle subjected to ultra-short magnetic fields — •Alexander Sukhov and Jamal Berakdar — Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Heinrich-Damerow-Str. 4, 06120 Halle/Saale

We consider theoretically the magnetization dynamics of a single ferromagnetic nanoparticle driven by ultra-short magnetic pulses. The macrospin approximation is employed based on a finite-temperature Landau-Lifshitz-Gilbert equation. For the case when the magnetic pulse duration is shorter than the field-free precessional period of the magnetization we utilize the local control theory [1] to obtain analytical expressions for the appropriate fields parameters that lead to swift magnetization switching or freezing [2]. The quality of this approximation and the reliability of the analytical expressions are endorsed by full numerical calculations that confirm our predictions. As an application we show how thermally assisted switching is realized by choosing the appropriate field parameters [3].

In the studies [2,3] the scheme was restricted to the case where the external fields were aligned in the plane perpendicular to the easy axis of the anisotropy. Recently we extended our study to the case where the field is applied at an arbitrary direction in space.

[1] R. Kosloff, A. D. Hammerich, D. Tannor, Phys. Rev. Lett. 69, 2172 (1992); [2] A. Sukhov and J. Berakdar, Phys. Rev. Lett. 102, 057204 (2009); [3] A. Sukhov and J. Berakdar, Phys. Rev. B 79, 134433 (2009).