Importance of vortex interactions in Tl2Ba2CaCu2O8 epitaxial films with columnar defects

The effects of columnar defects on electrical transport measurements in Tl2Ba2CaCu2O8 epitaxial films were found to persist up to magnetic fields of at least forty times the vortex matching field, that is, the field at which the vortex density corresponds to the density of columnar defects. This demonstrates the importance of interactions between vortices and is in contrast to experiments that suggest that the matching field has sharp significance.