The effect of pre-sintering and high-temperature infiltration on the properties of single-domain YBCO bulk superconductors by the Y+011 top-seeded infiltration growth process

The top-seeded infiltration growth process (TSIG) is one of the most important methods for the fabrication of single-domain rare-earth barium copper oxide (REBCO) bulk superconductors. The performance of samples is in the main closely related to the quality of the solid phase pellets (SPPs). In this paper, we report a new method for optimizing the SPPs and properties of single-domain REBCO bulks, including sintering of the SPPs (Y2O3 + BaCuO2), infiltration of the Ba-Cu-O liquid phase and the melting growth process. A group of single-domain YBCO bulk superconductors with a diameter of 20 mm have been fabricated by the modified RE + 011 TSIG method. Both the levitation force and the trapped field of the samples increase at first and then decrease with increase in the sintering time. The largest levitation force of 42.8 N and trapped field of 0.41 T (77 K, 0.5 T) are obtained in the sample sintered at 1000 degrees C for 4.5 h; this is mainly related to the optimal microstructure of the pre-sintered SPPs and the YBCO bulk. These results indicate that pre-sintering and high-temperature infiltration is a very important method for controlling the microstructure and improving the physical properties of single-domain YBCO bulk superconductors.