Submicron size Gd2BaCuO5 particles as source for large critical current densities in (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy

The effect of (Nd0.33Eu0.33Gd0.33)2BaCuO5 (NEG-211), and Gd2BaCuO5 (Gd-211) additions on melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy (NEG-123) composites are investigated using a combination of transmission electron microscopy (TEM) and measurements of critical current densities, Jc. TEM observations demonstrate that we could successfully embed submicron-size 211 particles within the NEG-123 matrix. EDX analysis revealed that these submicron-size particles consist mainly of Gd in the rare earth site. The presence of such 211 particles leads to a dramatic increase of Jc in low fields as well as in the high field region. For NEG-123 with an addition of 40 mol% of NEG-211 a critical current density of 70000 A/cm2 at 77 K, 2.2 T is observed for the field applied parallel to the c axis. (orig.)