Optimization of flux pinning and growth temperature for the top-seeded infiltration growth processing of a single grain bulk (Gd, Dy)BCO

Mixed REBa ₂ Cu ₃ O _7−γ (REBCO) superconductors are interested due to their superior flux pinning abilities. Various bulk superconducting applications required shape forming along with enhanced superconducting performance. The Infiltration Growth (IG) process allow to fabricate near net-shaped REBCO bulks and maintain high homogeneity in the microstructure compared to conventional melt growth process. However, IG process is sensitive to many parameters which need to be tuned for each system for high reproducibility. The primary factor for single grain growth of the REBCO bulk superconductors is optimization of flux pinning centers and finding an effective temperature window (nucleation and ending growth temperatures). This chapter reviews the optimization of Dy content in the IG processed single grain bulk GdBCO superconductors and the growth parameters for fabricating single grain. Isothermal dwells have been tested on the optimized composition of (Gd, Dy)BCO, at various undercooling temperatures to study the temperature window appropriate for the single grain growth in top-seeded IG process in air. A near net shaped, single grain (Gd, Dy)BCO crystal was grown. Systematic microstructural, elemental and their influence on superconducting performance was investigated. The possibilities for further improvement of the microstructure and superconducting performance were discussed.