VORTEX STATES AND PEAK EFFECT AT LOW TEMPERATURE IN THICK AMORPHOUS FILMS WITH WEAK PINNING

Abstract

We report on the dynamic as well as static properties of vortices in the low-temperature (T) solid phase of a thick amorphous Mo x Ge 1-x film with weak pinning. The vortex-solid state is considered to be a weakly disordered vortex lattice, which is inferred from the mode-locking resonance over the broad field region. The peak effect of the critical current Ic with magnetic field is clearly visible down to the lowest T measured (0.2 K), which corresponds to 3.3% of the superconducting transition temperature. We find that largest voltage noise originating from current-driven vortices appears in the field region just prior to the peak field at which Ic takes a peak. This is in accord with the result reported in NbSe 2 single crystals.