A fluctuating state and the critical behavior of the depinning transition in driven vortex matter in superconductors

Abstract

A status report is presented on explorations in 2H-NbS₂ which have revealed a new protocol that generates vortex states corresponding to two limiting ends of critical current density (J^l_c(H) and J^h_c (H)) for a given vortex density deep in the mixed state. An ordered vortex array set in motion with transport current I (I^l_c < I < I^h_c) explores its other option of non-moving jammed state of higher end I^h_c while steadily enhancing the driving force. Attempts to further unjam the re-pinned state unmask (i) a moving fluctuating state and (ii) the diverging (life) times along with an underlying critical behaviour at the threshold limit of de-pinning the disordered-jammed state, from both below as well as above I^h_c.