Voltage noise of current-driven vortices in disordered Josephson junction arrays

Dynamical phenomena of moving vortices and voltage noise spectra are studied in disordered Josephson junction arrays (JJAs). The plastic motion of vortices, smectic flow, and moving Bragg glass phases are separated by two dynamic melting transitions driven by current. From the voltage noise spectra of moving vortices, it is found that the driving current plays an important role in the melting of pinning vortices glass and ordering of moving vortices. The features of noise spectra obtained in the disordered JJA model have been observed recently in the high-temperature superconductor Bi2Sr2CaCu2Oy near the first-order melting transition, indicating that both of them are related to each other.