Dresden 2014 – scientific programme

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MA: Fachverband Magnetismus

MA 37: Spin Torque and Spin Excitations I

MA 37.6: Talk

Thursday, April 3, 2014, 11:00–11:15, HSZ 401

Influence of conduction electrons on spin dynamics — •Andreas Donges, Denise Hinzke, and Ulrich Nowak — University Konstanz, 78457 Konstanz, Germany

Current-induced domain wall (DW) motion due to the exchange interaction of s- and d-electron spins promises novel applications in data storage technologies [1]. However, when it comes to narrow DWs the spin-torque-description by Zhang and Li [2], used to describe this interaction, is not sufficient anymore and one has to take into account additional effects, such as spin-diffusion and spin-current-precession.

We numerically investigate current-driven DW motion in narrow walls using a 1-dimensional model, where localized d-electron spins are described by the Landau-Lifshitz-Gilbert-equation, whereas the equation of motion for the itinerant s-electrons has been derived from the spinor-Boltzmann-equation. Both equations are coupled via a local sd-exchange Hamiltonian and we neglect finite temperature effects. The DW velocity is studied in dependence of the wall width. We find a monotonic increase of the velocity with decreasing wall width, caused by non-equilibrium-spin-diffusion. Some systems show an additional rise in the DW velocity, when the wall width is near the spin-diffusion-length, that we link to the missing alignment of s- and d-electron-profiles.

[1] S. Parkin, et al., Science, 320, 5873 (2008)

[2] S. Zhang and Z. Li, Phys.Rev.Lett., 93, 12 (2004)