FLUX PINNING BY DISLOCATIONS IN DEFORMED MELT-TEXTURED YBA2CU3OX SUPERCONDUCTORS

The potential of flux pinning by dislocations to increase the critical current density (J(c)) of melt-textured YBa2Cu3Ox superconductors in a variety of orientations of magnetic field (H) with respect to the a- b plane was studied. The melt-textured samples were subjected to high temperature uniaxial and isostatic deformation to increase the disloca tion density. A broad peak in J(c) is observed in these samples at H p arallel-to c-axis and is attributed to point pinning by dislocations g enerated in the a-b plane by the deformation process. A sharp peak in J(c) is seen at 45-degrees to the a-b plane in some isostatically defo rmed samples. Edge type 1/6 [031] partial dislocations located at the boundary of the stacking faults observed along the [110BAR] zone axis of these samples are proposed to contribute to this peak. The results indicate that the J(c) of melt-textured samples can be enhanced in mag netic field orientations other than H parallel-to a-b by introduction of dislocations through high-temperature deformation processing.