Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 17: Spin Dynamics / Spin Torque II

MA 17.8: Talk

Wednesday, March 24, 2010, 16:15–16:30, H10

Dependence of Magnetic Domain-Wall Motion on a Fast Changing Current — •Lars Bocklage¹, Benjamin Krüger², Hauke Langner¹, Toru Matsuyama¹, Markus Bolte¹, Ulrich Merkt¹, Daniela Pfannkuche², and Guido Meier¹ — ¹Institut für Angewandte Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany — ²I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany

Domain walls in magnetic nanowires can be moved by an electrical current. Using resonant excitations the temporal shape of the current strongly influences the dynamics of the wall [1]. Theoretically it was predicted that the time derivative of the current density also affects the wall motion [2,3]. We observe a dependence of the depinning probability of a vortex wall on the rise time of current pulses in permalloy nanowires [4]. The characteristic time scale in which the rise time affects the depinning probability is in the order of some nanoseconds. An analytical description shows that a strong force acts on the domain wall for short rise times which arises from the time derivative of the current. The damping time of the domain wall, that is independent of the pinning potential, is the scaling time on which the force of the time derivative of the current gets significant. [1] L. Thomas et al., Nature 443, 197 (2006)

[2] B. Krueger et al., Phys. Rev. B 75, 054421 (2007)

[3] T. Suzuki et al., J. Appl. Phys. 103, 113913 (2008)

[4] L. Bocklage et al., Phys. Rev. Lett. 103, 197204 (2009)