Vortex-glass transition and vortex phase diagram in a thick amorphous MgxB1−x film

Abstract We present superconducting properties and vortex states in a thick amorphous Mg x B 1− x film with x =0.31. Measurements of dc and ac complex resistivities in the mixed state reveal the presence of the vortex-glass transition in three dimensions. Based on the data, we construct the vortex phase diagram in the field–temperature plane. We find that there is the relatively large vortex-liquid phase, which persists down to low temperatures.