Direct Determination of Large Spin-Torque Nonadiabaticity in Vortex Core Dynamics
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 β = 0:15 +/- 0:07, which is
more than an order of magnitude larger than the damping constant α, pointing to strong nonadiabatic
transport across the high magnetization gradient vortex spin structures.
Read the viewpoint "the alphabet of spin in nanostructures" by Rolf Allenspach and Philipp Eib
Read the viewpoint "the alphabet of spin in nanostructures" by Rolf Allenspach and Philipp Eib