Investigation of vortex dynamics close to B-c2 in Cu2Mo6S8 quasi epitaxialthin films

The Ginzburg number of superconducting Chevrel phases MxMo6S8 with small co herence length (10(-3) to 10(-5)) is intermediate between those obtained fo r conventional low T-c materials (10(-8)) and those of high T-c (10(-1)) in dicating that these phases may display features in the dynamics of the vort ices similar to those observed in high T-c superconductors. In this work we present a detailed study of I-V measurements close to the B-c2 line carrie d out on quasi epitaxial thin films of Cu2Mo6S8. The non-linear I-V curves show a scaling behaviour making possible to determine a transition temperat ure between an unpinned vortex state and a vortex glass state. However, the temperature range of the unpinned vortex state is much wider than expected .