Vortex Phase Diagram and Dynamics near T = 0 Probed by Voltage Noise in Amorphous Superconducting Films

Abstract

We report on the equilibrium vortex phase diagram and vortex dynamics driven by dc current at low temperature in a thick amorphous (a-)Vlo x Gsi_ x film with weak pinning. The vortex solid state is a weakly disordered vortex lattice, which is different from the disordered vortex glass for the a-Mo^Si^ films with stronger pinning. For both systems the liquid state is similar to each other, involving the quantum-vortex-liquid (QVL) phase at low temperature, where we detect large vortex-flow noise. The unusual flow persists even in the solid phase just below the QVL phase, while its amplitude is remarkably suppressed.