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 employed to find the pinning forces and resulting critical currents. The strain interactions are found to be uniformly repulsive for edge dislocations, while no strain interaction is predicted for screw dislocations. Calculations of the normal-state core-core interactions suggest that the reported [001] screw dislocation could behave as an effective pinning site. The results suggest that pinning by dislocations may be significant, producing J(c) in the range 10(3) to > 10(6) A cm-2, and that strain induced pinning will often appear to be point-like.