Improvement in field trapping capability of (Nd,Eu,Gd) Ba2Cu3Oy with Ag2O addition

We prepared (Nd,Eu,Gd) Ba2Cu3O7-delta (NEG-123) pellets of 22 mm diameter and 9 mm thickness with 10 mole% NEG-211, 0.5 mole% Pt, and various amounts of Ag2O ranging from 0 to 50 wt% using the oxygen-controlled melt-growth (OCMG) process. The irreversibility field increased with Ag2O content up to 20 wt%, and even with 50 wt% the magnetization loop was open at 77 K and 7 T. In the sample with 20 wt% Ag2O, a large critical current density of 10 kA cm(-2) was recorded even at 7 T and 77 K for fields applied parallel to the c-axis. The trapped field in the NEG-123 bulk was measured using a Hall probe at 77 K after field-cooling in 5 T. A single-peak profile observed in the sample with silver addition proved that silver dispersion is effective in improving mechanical properties without deterioration of electromagnetic properties.