FLUX-PINNING MECHANISMS IN THIN-FILMS OF YBA2CU3OX

We consider data from several experiments taken at very small induction in order to discern the nature of the pinning interaction in some thin-film samples of YBa2Cu3Ox with very large critical current densities. Analysis of typical pinning energies and critical current densities indicate that the pinning is due to a large density of point defects. We propose a simple model of pinning by point defects in the CuO2 planes that predicts a spacing between defects of 53. This large defect density may help to explain other properties of these films. © 1990 The American Physical Society.