THERMALLY ACTIVATED FLUX MOTION IN YBACUO THIN-FILMS - EXPERIMENTAL-EVIDENCE FOR THE TEMPERATURE-CURRENT SEPARABILITY OF THE ACTIVATION-ENERGY

On the basis of electric field-current density (E-j) isotherms experim entally determined on YBaCuO thin film microbridges, the previously as sumed separation ansatz U(T, B-e,j) = g(T, B-e)U-j(j) for the activati on energy for flux motion is tested over a wide range of current densi ties. Although the E-j data span approximately six decades in E and ca n be scaled according to the vortex glass theory, they do not allow an unambiguous proof of this model. This is demonstrated by showing that the data can be fitted to a model of thermally activated flux motion. An estimate is given for the necessary experimental resolution to dis tinguish between both models.