Improved superconducting properties due to Ag2O addition in NEG-123

We prepared NEG + 10 mol% N-EG-211 + 0.5 mol% Pt with 0-50 wt.% Ag2O, which are subjected to the oxygen-controlled melt-growth process. Microstructural observation showed that fine Ag particles are dispersed at lower Ag2O contents. At higher contents, Ag particles exhibited various sizes and shapes and segregated mostly in the vicinity of microcracks and pores. 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.% of Ag2O, a large critical current density of 10 kA cm(-2) was recorded even at 7 T and 77 K with the field applied parallel to the c-axis of the sample. (C) 2001 Elsevier Science B.V. All rights reserved.