Experiment for growing large Gd–Ba–Cu–O–Ag bulk superconductor

Abstract

Unmanned space experiments were performed with the aim of growing large grain Gd–Ba–Cu–O superconductors in space. The advantage of the space experiment was the support of a large precursor block by a small seed crystal alone. Three samples were safely returned from space. It was interesting to note that one of the samples was mainly composed of Gd 2BaO 4 pillar shaped crystals. Detailed characterization of this new phase showed that the phase is very stable under severe conditions and will be a firm framework for the melt growth process. Infiltration of Ba–Cu–O phase into a precursor Gd 2BaO 4 block enabled us to grow a large grain bulk Gd–Ba–Cu–O 14 cm in diameter.