Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.70: Poster

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

Temperature-Induced Magnetic Switching in Finite Chains — •David Bauer, Samir Lounis, Phivos Mavropoulos, and Stefan Blügel — Institut für Festkörperforschung and Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany

Understanding spin dynamics in magnetic nanostructures is important for applications in data storage. In particular the bistability of the magnetic state can lead to spontaneous switching and data loss at finite temperatures. For its investigation we adopt an approach on the basis of a classical spin model coupled to a heat bath. This requires the solution of the stochastic Landau-Lifschitz equations.

We apply this model to study the temperature-induced magnetic switching behavior of finite chains on surfaces. Different switching types are found, depending on the chain length, the exchange coupling constants and the magnetocrystalline anisotropy. A switch can occur either by coherent magnetization rotation, which is well described by an Arrhenius-Néel-law, or by a domain wall propagating through the chain after nucleation. We show that the domain-wall type of switching can be described by a combination of a random walk model and a modified Arrhenius-Néel-law. Furthermore, a possible strong increase of the anisotropy at the chain edges influences the switching time under certain contitions, related to the creation of an additional energy barrier acting against nucleation.