A novel method to fabricate single domain YBCO bulk superconductors without any residual liquid phase by Y+011 TSIG technique

Abstract

Top-seeded infiltration growth (TSIG) technique is a very important way for the fabrication of single domain YBCO bulk superconductors. But there are still two problems because of the usage of Y-based composite (such as YBa2Cu3O7-δ+Ba3Cu5O8) as liquid phase sources. One is that there are still exist some residues of liquid phase sources after TSIG process, which is an excess waste of materials; the other is that the residual liquid phase sources is difficult and have to be cut off from the single domain YBCO bulk. In order to overcome these problems, we proposed a new method to completely eliminate residual liquid phase sources by use a new liquid phase of (3BaCuO2+2CuO) to replace the traditional liquid phase (YBa2Cu3O7-δ+Ba3Cu5O8) and new solid phase of (Y2O3+BaCuO2) to replace the traditional solid phase Y2BaCuO5 during the TSIG process. The effects of (3BaCuO2+2CuO) content on the morphology, levitation force, microstructure and trapped field of the YBCO bulks have been investigated. It is found that single domain YBCO bulks can be fabricated with reasonable amount of new liquid phase source by TSIG process. The trapped field and levitation force of the YBCO bulk samples are of 0.3520 T and 40.85 N, which are higher than that of 0.3190 T and 37.21 N of the samples fabricated with the conventional liquid phases respectively. It is also found that the residues of the liquid phase sources have been completely eliminated by using reasonable new liquid phase source (3BaCuO2+2CuO). This provides a new way to fabricate high-quality single domain YBCO bulk superconductors with low cost, higher levitation force and without any residual liquid phase by TSIG process.