Dynamic phases and the peak effect in dirty type II superconductors
We study numerically and experimentally the dynamics of driven vortex matter. Our London-Langevin simulations find that the critical current exhibits a peak both across the Bragg glass to vortex glass transition and across the melting line. The peak is accompanied by a clear crossing of the I-V curves. We report transport measurements on untwinned YBCO crystals, in complete accordance with these findings. At higher drives disorder is averaged to reduced values, and in three dimensions the vortices reorder into a "moving solid." The effect of the disorder can be well represented with a "shaking temperature" which is inversely proportional to the velocity.
van Otterlo A
Physics Department, University of California, Davis, California 95616, USA.
Scalettar
RT
Zimanyi
GT
Olsson
R
Petrean
A
Kwok
W
Vinokur
V