THE EFFECT OF AL DOPING ON THE CRITICAL SCALING OF YBA2CU3O7 FILMS, IN HIGH MAGNETIC-FIELDS

We present current-voltage characteristics (I-V) in YBa2(Cu1-xAlx)3O7 films (0 less-than-or-equal-to x less-than-or-equal-to 0.03), in magne tic fields 0.5 less-than-or-equal-to B less-than-or-equal-to T, which am consistent with the existence of a phase transition with critical e xponents and scaling functions independent of Al concentration. We stu dy the role of Al doping in flux pinning by analyzing the non-universa l characteristics of the transition such as the width of the critical regime, the characteristic length for vortex correlations, and the tem perature and the resistivity that correspond to the onset of the criti cal response.