The effect of pointlike disorder on current-driven vortex state of Bi 2Sr 2CaCu 2O 8+ δ

Abstract

We studied the DC current-driven vortex state of a Bi 2Sr 2CaCu 2O 8+ δ model in the presence of pointlike disorder via a Monte Carlo simulation. We found that the vortex drift velocity v as a function of temperature T drastically changes twice at a depinning ( T dp) and a melting ( T m) temperature, as is consistent with our two-stage melting scenario. At the low field region, whereas v remains almost zero for T< T dp, it rapidly grows for T dp< T< T m and the Bragg peak intensity survives for T< T m. We thus give numerical evidence that a moving Bragg glass phase exists for the intermediate temperature regime of T dp< T< T m.