Transport measurements on granular YBaCuO films

Abstract The critical current in granular YBaCuO films has been measured at temperatures very near the critical temperature, T c . The critical current is proportional to (1-T/T c ) 2 for T c . The current-voltage (I–V) characteristics of the films have also been measured as a function of temperature and indicate that the observed deviation from the (1-T/T c ) 2 dependence for T > .9T c is a natural consequence of the constant field criterion (e.g. .25 μV/mm) used to define the critical current.