Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 30: Electron Theory
MA 30.3: Vortrag
Donnerstag, 28. Februar 2008, 15:00–15:15, H 1028
An improved s-d model for the dissipative domain wall dynamics — •Lorenzo De Angeli and Manfred Fähnle — Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany
The dissipative dynamics of domain walls induced by an external magnetic field or by spin-polarized transport currents is often described within the framework of the s-d model [1]. Thereby the magnetization is subdivided into a localized part Md(r,t) arising from the d electrons and a part m(r,t) due to the conduction s and p electrons, and the dynamics of Md(r,t) is influenced by the torques exerted on the localized magnetization by m(r,t). A basic assumption of the conventional s-d model is that in a static situation the atomic moments arising from Md and m are collinear. It has been shown that for strongly noncollinear situations (e.g., narrow domain walls, vortex cores, etc.) this assumption is not correct [2]. We have extended the s-d model by taking into account a possible noncollinearity between the d magnetization and the conduction electron magnetization, leading to various new torques. By extending the Walker model for the dynamics of domain walls [3] the influence of such torques on the initial and final velocity of a Neel wall is investigated.
[1] S. Zhang and Z. Li, Phys. Rev. Lett. 93, 127204 (2004).
[2] M. Fähnle, R. Singer and D. Steiauf, Phys. Rev. B 73, 172408 (2006).
[3] N.L. Schryer and L.R. Walker, J. Appl. Phys. 45, 5406 (1974).