DISLOCATION-INDUCED FLUX-PINNING INTERACTIONS IN YBA2CU3O7

The interactions of flux lines with dislocation lines in YBa2Cu3O7 are modelled for both strain-field interactions and core-core overlap. A numerical calculation of the strain-induced interaction energy is empl oyed to find the pinning forces and resulting critical currents. The s train interactions are found to be uniformly repulsive for edge disloc ations, while no strain interaction is predicted for screw dislocation s. Calculations of the normal-state core-core interactions suggest tha t the reported [001] screw dislocation could behave as an effective pi nning site. The results suggest that pinning by dislocations may be si gnificant, producing J(c) in the range 10(3) to > 10(6) A cm-2, and th at strain induced pinning will often appear to be point-like.