3D X-Y SCALING OF THE RESISTIVITY AND THE EFFECT OF DISORDER IN YBA2CU3O7-DELTA THIN-FILMS

We present measurements for the resistivity of 'c' axis oriented YBa2C u3O7-delta (YBCO) films grown on (100) SrTiO3 substrates by both Laser Ablation and ion beam sputtering. The effect of the magnetic field on the resistivity is investigated with the field parallel to the 'c' ax is. The zero field transition widths vary from 1K to 4K in different f ilms. However the data exhibits 3d X-Y critical scaling having introdu ced an 'effective' magnetic field characteristic of the length scale o f the disorder in the film.