Vortex phase diagram and vortex dynamics at low temperature in a thick a-MgxB1-x film

We report on the equilibrium vortex phase diagram and vortex dynamics at low temperature T in a thick amorphous (a-)MgxB1-x film based on the measurements of the dc resistivity p and time (t)-dependent component of the flux-flow voltage, delta V(t), respectively. Both rho(T) in perpendicular fields and the vortex phase diagram are qualitatively similar to those for the a-MoxSi1-x films, in which evidence for the quantum-vortex-liquid (QVL) phase has been obtained. In either material system we observe anomalous vortex flow with the asymmetric distribution of delta V(t) in the QVL phase, suggesting that the anomalous flow is a universal phenomenon commonly observed for disordered amorphous films, independent of material. (c) 2007 Elsevier B.V. All rights reserved.