Effect of liquid phase mass for the production of single grain infiltration growth processed bulk YBa2Cu3Oy by YbBa2Cu3Oy+Liquid phase as a liquid source

Abstract

The efficient production of single grain YBa2Cu3O7-δ (Y-123) bulks via top-seeded infiltration growth (IG) process demands optimized liquid phase (in the given case a mixture of Y-123 and Ba3Cu5O8). This enables a smooth peritectic growth and results in high quality bulks. Recently, 1:1 mixture of Y-123 and Ba3Cu5O8 has been considered as an optimum. In the search for a further optimized mixture to attain a longer c-axis growth, we tested Yb-123 + Ba3Cu5O8 liquid mixture varying the liquid phase (LP) amount, i.e. Yb-123 + liquid (1:1; 1:1.2; and 1:1.3). Using these liquid phase concentrations, Y-123 blocks were isothermally grown at 995 °C for 50 h with following slow cooling. Single-grain Y-123 blocks of 20 mm diameter and 7 mm thickness were fabricated. We present detail properties of the bulk Y-123 prepared with the liquid source of Yb-123 + Ba3Cu5O8 (1:1.3). A sharp superconducting transition with Tc,onset at 90 K and critical current density (Jc) at 77 K of around 40 kA/cm2 and 13 kA/cm2 in self-field and 2 T (H//c-axis), respectively, were observed. Trapped field showed a typical single cone profile with maximum value of 0.4 T at 77 K, 0.3 mm above top centre of the bulk Y-123. It is more than triple value for the same size and a similar material reported so far for bulk Y-123 prepared with Yb-123 + Ba3Cu5O8 (1:1) as a liquid source.