Event Details
Ultrafast spin dynamics in thin film microstructures: Experiments and Micromagnetic simulations
Presenter: Dr. B.C. Choi, Dept. of Physics, UVIC
Supervisor:
Date: Mon, November 25, 2002
Time: 15:00:00 - 16:00:00
Place: EOW 430
ABSTRACT
In this talk, spatiotemporal magnetization reversal dynamics in Ni80Fe20 mesoscopic elements investigated using ps time-resolved scanning Kerr microscope will be presented. Magnetic domain images reveal a striking change in the reversal, associated with a reduction in switching time when a transverse bias field is applied. According to the analysis of time-domain images, the abrupt change of the switching time is attributable to a change in the magnetization reversal mode: the nucleation dominant reversal process is replaced by quasicoherent domain wall motion in the presence of an additional transverse biasing field.
Observations of spontaneous dynamic domain pattern formation in mesoscopic thin film elements with various aspect ratios will be also reported. Well-developed labyrinth- or stripe-shaped dynamic domain patterns are formed in response to short magnetic pulses. The unmistakable signature of dynamic domain pattern formation is found in the strong dependence on the speed at which the magnetization reversal is driven.
The experimental results are compared to micromagnetic modeling, based on the Landau-Liftshitz-Gilbert equation. The observed distinct magnetization reversal behaviors dependent on applied field conditions are well reproduced in the simulations.
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For further information, contact Harry Kwok at 721-8685 or Donna Shannon at 721-8821.