It was noted that solidification introduced defects into melt-grown bulk samples. The most important such microstructural features were sub-grain boundaries, and a macroscopic inhomogeneity of the composition. It was shown here that growth in sectors was responsible for the macroscopic arrangement of the defects in a sample. A mechanism for sub-grain formation was proposed which was based upon the formation of dislocations during the engulfing of RE2BaCuO5 particles by the growth of Cu3Ba2REOy.

Growth-Related Microstructure of Melt-Grown REBa2Cu3Oy Bulk Superconductors. P.Diko: Superconductor Science and Technology, 2000, 13[8], 1202-13