Abstract

Fast dynamics of domain walls and vortices occur on the sub-nanosecond
time scale. We image oscillations of a single magnetic domain wall in
a confining potential by time resolved x-ray microscopy with a spatial
resolution of 25 nm and a temporal resolution of 70 ps [1]. The
oscillation of the domain wall is triggered by nanosecond current
pulses. The spin-polarized current and the accompanying Oersted field
can contribute to the motion of the wall.
In micron-sized permalloy squares the magnetic ground state forms a
vortex. A deflected vortex core gyrates around its equilibrium
position typically in the frequency range below 1 GHz. Here we present
our experiments on polarization reversal using rotating currents [2].

[1] L. Bocklage, B. Krüger, R. Eiselt, M. Bolte, P. Fischer, and G.
Meier, Phys. Rev. B 78, 180405(R) (2008).
[2] M. Bolte, G. Meier, B. Krüger, A. Drews, R. Eiselt, L. Bocklage,
S. Bohlens, T. Tyliszczak, A. Vansteenkiste, B. van Waeyenberge, K. W.
  Chou and H. Stoll, Phys. Rev. Lett. 100, 176601 (2008)"