NONLINEAR IV CHARACTERISTICS OF A C-AXIS-ORIENTED TL2BA2CA2CU3OX THIN-FILM

We have measured the current-voltage characteristics of a c-axis-oriented Tl2Ba2Ca2Cu3Ox thin film with relatively wide transition and a small tail, and found that the relation between V and I in the transition region follows the form : V ?? (I-Ic)N, where Ic is the critical current. The exponent N increases as the temperature decreases and rises abruptly from 1 to 1.5 near the zero resistance transition temperature Tc2, where an amount of grains pass into superconducting phase indicated by magnetic measurements. It is explained on the basis of fluctuation described by the time-dependent Ginzburg-Landau equations.Physics, Condensed MatterSCI(E)EI0ARTICLE3345-3477