Superconducting joint of Y-Ba-Cu-O superconductors using Er-Ba-Cu-O solder

Two melt-textured Y-Ba-Cu O superconductor blocks were successfully welded with Er-Ba-Cu-O solder having a lower peritectic temperature than that of Y-Ba-Cu-O. The key to a strongly coupled joint was a combination of the control of crystal growth along (1 1 0) direction and the employment of a highly dense sintered Er-Ba-Cu-O bar as a solder material. Microstructural analyses revealed that no segregation of secondary phase and/or residual liquid phase was observed at the joint interface. Furthermore, it was found through magneto-optical observations that magnetic field could not penetrate into the joint, indicating that the two superconductors were strongly connected with this method. (C) 2001 Elsevier Science B.V. All rights reserved.