Novel approach for manufacture of single‐grain EuBCO/Ag bulk superconductors via modified single‐direction melt growth
Filip Antončík, Michal Lojka, Tomáš Hlásek, David Sedmidubský, Josef Baumann, J H Durrell, D A Cardwell, Ondřej Jankovský
Abstract
Abstract Despite the success of top‐seeded melt growth (TSMG) and TSIG, some key aspects of their manufacture need to be addressed including the presence of microstructural defects, inhomogeneities in trapped field and the difficulty of growing large‐diameter bulk monoliths. Recently, a promising new method single‐direction melt growth (SDMG) appears to address the majority of the shortcomings of TSMG and TSIG. Single‐grain EuBCO/Ag bulk with the highest peritectic temperature to date was grown by modified SDMG. This remarkable achievement was made possible by lowering the peritectic temperature of the precursor composition by the addition of silver and by using single‐grain EuBCO fabricated by TSMG as a seed. The EuBCO/Ag bulk grown by SDMG has demonstrated significant improvements in comparison to a reference TSMG sample. A reduction of approximately 30% in defect area (associated primarily with porosity), as well as a significantly enhanced homogeneity of trapped field and critical temperature, was observed. Furthermore, the critical current density curves exhibit a considerable improvement, particularly in the 2–5 T field range. The SDMG technique has considerable potential for scale‐up for the fabrication of large‐diameter bulk single grains, with only growth along the c ‐axis involved during the thermal process.