INFLUENCE OF LATTICE MISMATCH ON FLUX-PINNING IN (RE,Y)BA2CU3O7-DELTA

Flux pinning by stress field of lattice mismatch has been researched in RE-123 superconductor. The studies focus on the interaction between a magnetic flux lineand a lattice defect which is the lattice mismatch induced by substitution of other rare earth for Y in (RE,Y)Ba2Cu3O7-delta. By establishing an effective-defect-model, we get the stress field of lattice mismatch. Further, a calculation on pinning strength has been performed for a flux lines in such stress field. Numerical evaluation shows that such pinning force is of the same order magnitude as that for conventional superconductors. The calculating result demonstrates that the lattice misfit by rare-earth dopants can become the effective pinning centers under the appropriate doping level.