Fabrication of single domain GdBCO bulk superconductors by a new modified TSIG technique

• Single domain GdBCO bulks fabricated by TSIG method with new solid and liquid phases (a mixture of Gd2O3+10BaCuO2+6CuO) instead of the conventional liquid phase (GdBa2Cu3O7-x + Ba3Cu5O8).
• The new solid phases is a mixture of Gd2O3+BaCuO2.
• The new liquid phase is a mixture of Gd2O3+10BaCuO2+6CuO.
• Levitation force of GdBCO bulks fabricated with new solid phase is higher.
• Nanometer particles about 260 nm were found in the samples by this new method.

Single domain GdBCO bulk superconductors have been fabricated with new and traditional solid phases by a top seeded infiltration and growth (TSIG) process technique. In the conventional TSIG process, three types of powders, such as Gd2BaCuO5, GdBa2Cu3O7−x and Ba3Cu5O8, must be prepared, but in our new modified TSIG technique, only BaCuO2 powders are required during the fabrication of the single domain GdBCO bulk superconductors. The solid phase used in the conventional process is Gd2BaCuO5 instead of the solid phase (Gd2O3 + BaCuO2) utilized in the new process. The liquid phase used in the conventional process is a mixture of (GdBa2Cu3O7−x + Ba3Cu5O8), and the liquid phase in the new process is a mixture of (Gd2O3 + 10BaCuO2 + 6CuO). Single domain GdBCO bulk superconductors have been fabricated with the new solid and liquid phases. The levitation force of the GdBCO bulk samples fabricated by the new solid phase is 28 N, which is slightly higher than that of the samples fabricated using the conventional solid phases (26 N). The microstructure and the levitation force of the samples indicate that this new method can greatly simplify the fabrication process, introduce nanometer-sized flux centers, improve the levitation force and working efficiency, and greatly reduce the cost of fabrication of single domain GdBCO bulk superconductors by the TSIG process.