(001)MGO SINGLE-CRYSTAL AS A REACTION-BARRIER MATERIAL FOR MELT PROCESSING OF Y-BA-CU-O SUPERCONDUCTOR

The usefulness of a (001) MgO single crystal as a reaction-barrier material for melt processing was examined by investigating the microstructure near the interface between the MgO and melt-textured Y-Ba-Cu-O superconductors. It is found that there is no reaction among a (001) MgO single crystal and phases produced during peritectic decomposition/reaction, and no wetting of a Ba-Cu-O liquid phase on the (001) surface. After melt processing, the Y-Ba-Cu-O/MgO interface was clean except for the presence of a semi-continuous CuO-based liquid layer at the interface. Furthermore, the used MgO plate was easily separated from the melt-textured sample because of no chemical/physical bonding between two materials. Therefore, it can be used repeatedly. A (001) MgO single crystal is recommended as a good supporting plate or a crucible material for fabrication of Y-Ba-Cu-O single crystal and bulk superconductor using melting technique.