Processing of bulk YBaCuO

The author summarizes processing of bulk YBa₂Cu₃O_x superconductors with an emphasis placed on the relationship between microstructure and critical currents. Sintering is commonly used in ceramic processing but has been unsuccessful in producing high-J_c materials, primarily due to the weak links at grain boundaries. Melt processes have been found to be effective in increasing J_c values through a combination of grain alignment and the introduction of pinning centres. Some possible applications of melt processed superconductors in bulk form are also introduced in this review. Although many attempts have been made to fabricate long conductors, J_c values are still very small for long conductors, while the length is limited for high-J_c materials.