Abstract
We use a pump-probe photoemission electron microscopy technique to image the displacement of vortex cores in Permalloy discs due to the spin-torque effect during current pulse injection. Exploiting the distinctly different symmetries of the spin torques and the Oersted-field torque with respect to the vortex spin structure we determine the torques unambiguously, and we quantify the amplitude of the strongly debated nonadiabatic spin torque. The nonadiabaticity parameter is found to be , which is more than an order of magnitude larger than the damping constant , pointing to strong nonadiabatic transport across the high magnetization gradient vortex spin structures.
- Received 17 June 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.187203
© 2010 The American Physical Society
Viewpoint
The alphabet of spin in nanostructures
Published 25 October 2010
A robust measurement scheme indicates that a spin-related torque that speeds up moving domain walls in magnetic nanostructures is larger than previously estimated.
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