OBSERVATION OF VORTEX-GLASS-TO-LIQUID TRANSITION IN THE HIGH-T(C) 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 less-than-or-equal-to 1.2 T, with critical exponents nu = 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.