YBCO-Buffered NdBCO Film with Higher Thermal Stability in Seeding REBCO Growth and Recycling Failed Bulk YBCO Superconductors

In this work, we report a strengthened super- heating effect caused by a buffering YBa2Cu3Oy (YBCO or Y123) layer in the Nd1+xBa2−xCu3O7−y (NdBCO or Nd123) thin film with MgO substrate (i.e., NdBCO/YBCO/ MgO thin film). In the cold-seeding melt-textured (MT) growth, the NdBCO/YBCO/MgO film presented an even higher superheating level, about 20 °C higher than that of nonbuffered NdBCO film (i.e., NdBCO/MgO film). Pole figure (X-ray Φ-scan) measurement reveals that the Nd- BCO/YBCO/MgO film has better in-plane alignment than the NdBCO/MgO film, which may be the main origin of the enhanced thermal stability. Using this NdBCO/YBCO/MgO film as the seed and under a maximum processing temper- ature (Tmax) up to 1120 °C, we succeeded in growing vari- ous RE1+xBa2−xCu3O7−y (REBCO, RE = Gd, Sm, Nd, RE refers to rare elements) bulk superconductors and recycling the failed REBCO (RE = Y) bulks in a simple and feasible process.