Microstructure within domains of melt-processed YBa2Cu3O7-x superconductors

The microstructure within single domains of melt-processed YBa2Cu3O7-x (1:2:3) material has been examined. Rather than composing a brick-wall structure, the stacked, parallel platelets within the domains are actually portions of a single crystal. A growth mechanism is proposed that is consistent with the observed microstructural features. The anisotropic nature of the growth of 1:2:3 results in gaps separating the platelets. The gaps, however, terminate within domains, resulting in interconnected single-crystalline material. The absence of weak-link behavior for current flow along the c axis and the high critical-current densities observed within domains of melt-processed 1:2:3 material are readily explained by the fact that current flow is solely through single-crystalline material.