Motion of current-driven vortex solids in the Corbino-disk of amorphous superconducting films

Abstract

We study the dynamic properties of the vortex-solid driven by a radial current I in the Corbino-disk (CD) of a thick amorphous a-Mo x Si 1− x film with moderately strong pinning and a thick a-Mo x Ge 1− x film with weaker pinning. In CD, vortices rotate around the center of the sample by feeling a Lorentz force f L inversely proportional to the radius r of rotation. We measure the voltages, V( r 12) and V( r 23), induced at the two voltage probes placed radially ( r 12 < r 23), as a function of f L (or I). For both films the initial dynamic state of driven solid is the plastic flow, indicating significant pinning effects. For the a-Mo x Si 1− x film the large difference between V( r 12) and V( r 23) is observed at lowest I, which is attributed to the stronger pinning effects in the a-Mo x Si 1− x film.