Anisotropic phase diagram at higher temperature for Tl2Ba2CaCu2O8 thin film

By measuring the temperature dependence of the magnetoresistivity of Tl2Ba2 CaCu2O8 thin films, two superconducting transitions were observed for field orientations in the H perpendicular to ab- and H // ab-planes. The transit ion at the high temperature (T-ch) corresponds to a steep peak in the deriv ative of the effective activation energy and shifts very moderately with in creasing magnetic field. The transition is in good agreement with the value of the upper critical field derived from critical fluctuation theory. Mean while, the transition at low temperature (T-cl) was associated with the Jos ephson coupling and strong intrinsic pinning for the two field orientations , respectively. This is consistent with the different magnetic field depend ence of the activation energy calculated from the experimental data between T-ch and T-cl.