Abstract

Top Seeded Melt Growth (TSMG) has been used extensively to fabricate large, single grain Y-Ba-Cu-O (YBCO) superconductors that can trap large magnetic fields. The TSMG method is economical and has enabled the development of batch processes for the fabrication of a large number of bulk single grain superconductors in a single furnace. In addition, the technique allows the fabrication of complex-shaped bulk samples with controlled and strongly connected grains by using a multi-seeding process. A practical processing route for processing of LRE -Ba-Cu-O single grain superconductors (which have superior properties to YBCO ) has been developed at Cambridge over the past three years based on the development of a generic seed of melt-textured Mg-doped Nd-123 and suppression of solid solution phase formation in air by enriching the precursor composition with excess Ba. We report the successful application of a practical TSMG process to the fabrication of high performance Gd-Ba-Cu-O (GdNBCO) single grain superconductor. This method has enabled the development of a batch process for GdBCO and we demonstrate for the first time the fabrication of a large number of high performance Gd-Ba-Cu-O single grains in a single process. Finally, we report the processing of bulk GdBCO in the form of complex geometries with controlled grain orientation.