Vortex lattice melting in perforated Nb/(Cu-Mn) multilayers

We report the results of transport measurements in perforated superconducting (Nb)-spin-glass (Cu-Mn) multilayers. Current-voltage (I-V) characteristics were measured as a function of the temperature T, magnetic field H and sample anisotropy gamma(o). The noise and the hysteresis in the I-V curves were observed only for certain values of temperature and magnetic field, dependent on the anisotropy value. Outside these values both the noise and the hysteresis vanished. Among the possible mechanisms responsible for this, the quantum melting of the vortex lattice seems to be the most appropriate in describing the experimental data. The dynamic phase diagram is reproduced for samples with different anisotropies.