Authors: O.V. Dobrovolskiy, V.M. Bevz, E. Begun, R. Sachser, R.V. Vovk, and M. Huth
Phys. Rev. Applied 11, 054064
Abstract: The dynamics of Abrikosov vortices in superconductors is usually limited to vortex velocities v≈1 km/s, above which samples abruptly transit into the normal state. In the Larkin-Ovchinnikov framework, near the critical temperature, this transition is because of a flux-flow instability triggered by the reduction of the viscous drag coefficient due to the quasiparticles leaving the vortex cores. While the existing instability theories rely upon a uniform spatial distribution of vortex velocities, the measured (mean) value of v is always smaller than the maximal possible one, since the distribution of v never reaches the δ-functional shape. Here, by guiding magnetic flux quanta at a tilt angle of 15∘ with respect to a Co nanostripe array, we speed up vortices to 3–6 km/s. These exceed v in the reference as-grown Nb films by almost an order of magnitude and are only a factor of about 3 smaller than the maximal vortex velocities observed in superconductors so far. We argue that such high v values appear in consequence of a collective dynamic ordering when all vortices move in the channels with the same pinning strength and exhibit a very narrow distribution of v. Our findings render the well-known vortex guiding effect to open prospects for investigations of ultrafast vortex dynamics.