Flux-flow noise in the vicinity of the peak effect

Strong flux-flow voltage noise, commonly observed in the vicinity of the peak effect in superconductors, is ascribed to a novel noise mechanism. Random injection of the strongly pinned metastable disordered vortex phase through the sample edges and its subsequent random annealing into the weakly pinned ordered phase in the bulk result in large critical current fluctuations causing large vortex velocity fluctuations. In the Corbino disk configuration vortices do not cross sample edges, the injection of the metastable phase is prevented, and accordingly the excess noise is absent.