Observation of vortex-glass-to-liquid transition in the high-${\mathit{T}}_{\mathit{c}}$ superconductor ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{Ca}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{10}$

We report a series of measurements of I-V curves for a c-axis-oriented ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{Ca}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{10}$/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 ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{Ca}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{10}$/Ag tapes at a given temperature and magnetic field.