Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.57: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Current-driven domain walls in nanowires — •Benjamin Krüger1, Daniela Pfannkuche1, Markus Bolte2, Guido Meier2, and Ulrich Merkt2 — 1I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstrasse 9, 20355 Hamburg — 2Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg
Current-induced motion of a domain wall in a semicircle nanowire with an applied Zeeman field is investigated. Starting from the micromagnetic equation of motion extended by the adiabatic as well as the non-adiabatic current-induced spin torque introduced by Zhang and Li [1], we derive an analytical solution characterizing the domain-wall motion as a harmonic oscillation. This solution relates the micromagnetic simulation parameters with the dynamical characteristics of a harmonic oscillator. The results are compared to numerical calculations. For these calculations we extended the Object Oriented Micromagnetic Framework (OOMMF) [2] with the current-induced spin torques. The numerical calculations confirm our analytical solution. Our calculations disclose a strong dependence of the motion and the structural changes of the wall on the Gilbert damping and the non-adiabatic spin torque. For wires with strong curvature the dipole moment of the wall as well as its geometry influence the eigenmodes of the oscillator. Based on these results we suggest experiments for the determination of material parameters which otherwise are difficult to access.
[1] S. Zhang and Z. Li, PRL 93, 127204 (2004).
[2] M. J. Donahue and D. G. Porter, http://math.nist.gov/oommf