Plastic Motion of Current-Driven Vortex Glass in the Corbino Disk

Abstract

We report on current–voltage (I–V) characteristics for a thick amorphous Mo_xSi_1−x film both in conventional strip-like and Corbino-disk (CD) contact geometries. In CD, vortices rotate around the sample center and we can control the gradient as well as the strength of the Lorentz force acting on the vortices. In the vortex-liquid phase, we find no significant difference in the shape of I–V curves between the two geometries, while in the vortex-glass phase anomaly in the I–V curves is visible in CD as a dip in dlogV⁄dlogI at a characteristic current I^*. Using recent simulation work by Miguel and Zapperi, we suggest that a change in the vortex dynamics from plastic flow to laminar (liquid-like) flow occurs at approximately I^*.