Fabrication of large melt-textured GdBaCuO superconductor with Ag addition

Abstract

Large c-axis oriented GdBaCuO bulk superconductors with Ag addition were melt-textured under controlled oxygen partial pressure of 1.0%. Nd123 was used as a seed crystal for the growth of large grain bulk. Single grain GdBaCuO samples of diameters 32 mm and 48 mm were successfully fabricated with no macro-sized cracks. Using fine Gd211 powder as a starting material remarkably reduced the size of 211 particles dispersed in the bulk. As a result, high critical current density ( J c) of 6000 – 70000 A/cm 2 in a selffield was achieved at 77K. The trapped magnetic fields of the samples 32 mm and 48 mm in diameter reached 1.5T and 1.8T at 77K, respectively. These values are comparable to that of a melt-textured SmBaCuO bulk in similar size, and exceeds those of an YBaCuO bulk and the previous GdBaCuO bulk.