Transport properties of a Tl-2201 film close to the critical temperature: The vortex glass transition

We have studied the I-V characteristics of a Tl-2201 plm at zero field In t he regime in which flux creep is the dominant dissipation mechanism, the J( c)-T curve is divided into two parts at a temperature T-g (about 82 K), clo se to the critical temperature (84 K), The I-V characteristics around T-g a re well described using a flux creep model. For T>T-g, J(c)/J(c) (0) =0.445 x(1-0.525t-0.5t(2)); for T<T-g, J(c)/J(c)(0) = 0.9x(1-0.595t-0.44t(2)). Dif ferential resistance (dV/dI) as a function of the measuring current shows a change in curvature close to T-g, The I-V curves collapsed nicely into two branches by plotting (V/I)/ /T-T-g/ (V(z-1)) vs (I/T)/ /T-g-T/(2V), indica ting a current-reduced vortex glass transition.