Field-induced crossover of criticalities of vortex dynamics in Tl2Ba2CaCu2O8 thin films

By analyzing I-V characteristics (E-B curves), which were experimentally determined on Tl2Ba2CaCu2O8 thin films in magnetic fields B-e varying from 0 T to 5 T, we find that the transition of the linear resistivity rho(lin) = [E/j](j-->0) signaling superconductivity exhibits different criticalities for different magnetic fields. Starting with a Berezinskii-Kosterlitz-Thouless transition at T-BKT = 103.7 It for B-e = 0 T, one induces a crossover to a quasi-2D or 3D vortex-glass transition at a finite T-g for magnetic fields below a few kOe, and finally a "true" 2D vortex-glass with T-g = 0 K for higher fields. We argue that this field-induced crossover of criticalities is a general feature of all strongly anisotropic high-T-c superconductors.