Influence of Y₂BaCuO₅ particles on the growth morphology of peritectically solidified YBa₂Cu₃O_7−x

Modifications of a recent model by Izumi et al.¹ on diffusion controlled growth of YBa₂Cu₃O_7−x (123) superconductors are proposed, taking into account especially the engulfment process of the Y₂BaCuO₅ (211) particles into the solidifying 123 interface. The proposed modifications are evidenced by experimental results and applied to explain microstructural features of the 123 superconducting material. In particular, the 1:1 correlation between 123 platelet thickness (planar defect spacing) and 211 particle size as described by Jin et al.² is explained by an observed bridge growth resulting in a zipper-like mechanism. By this mechanism the platelets grow together in an oriented way leading to a quasi single crystalline material.