Driven vortices in type-II superconductors: A muon spin rotation study

We present a detailed study of vortex motion in a type-II superconductor using the muon spin rotation (μSR) technique. The vortices were set in motion by an alternating transport current. By adjusting the frequency and amplitude of the driving force so that vortices "visible" to the implanted muons did not cross the sample boundaries, a μSR line shape was obtained corresponding to almost perfectly ordered vortex motion. We also observed sidebands to the μSR line shape which correspond to the frequency at which vortices pass the implanted muon, and allow a direct measurement of the vortex velocity. Both these features of the line shape confirm numerical predictions reported in a previous study [see Charalambous, Phys. Rev. B 66, 054506 (2002)]. © 2006 The American Physical Society