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

Abstract

Top-seeded infiltration growth process (TSIG) is one of the most important methods for the fabrication of single domain REBCO bulk superconductors, the performance of the samples are mainly closely related with quality of the solid phase pellets. In this paper, we report a new way on how to optimize the solid phase pellets and the properties of the single domain REBCO bulks, including sintering of the solid phase pellets (Y2O3 + BaCuO2), infiltrating 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 of the levitation force and trapped field of the samples are increasing first and then decreasing with the increasing of sintering times. The largest levitation force 42.8 N and trapped field 0.41 T (77 K, 0.5 T) is obtained in the sample which was sintered at 1000 ℃ for 4.5 hours, which is mainly related with the optimal microstructure of the pre-sintered solid phase pellets and the YBCO bulk. The results indicate that pre-sintering and high temperature infiltration is a very important method to control the microstructure and improve the physical properties of single domain YBCO bulk superconductors.