Observation of vortex-glass-to-liquid transition in the high-Tc superconductor Bi2Sr2Ca2Cu3O10

We report a series of measurements of I-V curves for a c-axis-oriented Bi2Sr2Ca2Cu3O10/Ag tape immersed in liquid oxygen. By applying the critical scaling analysis to the I-V characteristics measured in various magnetic fields, a vortex-glass-liquid phase-transition line was identified in the mixed state of this system for H≤1.2 T, with critical exponents ν=1.25±0.15 and z=8.5±1.5. We also show that this transition boundary in the H-T plane defines the upper limit of useful current carrying capacities for the Bi2Sr2Ca2Cu3O10/Ag tapes at a given temperature and magnetic field.