Film thermal stability correlation with seeding modes in the growth of YBa₂Cu₃O_7−δ crystals

High-quality and large YBa₂Cu₃O_7−δ (YBCO or Y123) single crystals are necessary for both fundamental studies and practical applications. The recently exploited modified melt growth (MMG) procedure realizes a high efficiency of growth and high purity of Y123. However, it was unexpectedly found that the thermal stability of the NdBa₂Cu₃O_7−δ (Nd123) film seed applied in MMG is greatly reduced owing to a change in the liquid property. In order to solve this problem, a new top-seeding mode, buried seeding, is developed to strengthen the film thermal stability, leading to a remarkable enhancement of endurable maximum processing temperature of over 30 K in low supersaturation. Furthermore, the correlation of the thermal stability of the film seed in melt growth with the liquid property and top-seeding modes is clarified. Most importantly, the buried-seeding mode was successfully applied in this work, opening a promising pathway for the effective growth of single crystals of other REBCO (RE = Nd, Sm, Gd) oxides (possessing a higher peritectic temperature than YBCO), as well as other functional oxides.