Very high trapped field in melt-processed Sm-Ba-Cu-O

We prepared c-axis oriented Sm-Ba-Cu-O bulk-superconductors by the melt-pro cess technique in a reduced oxygen atmosphere. We particularly studied the effect of Ag addition to the composite in the present work, because Ag was found to greatly suppress the formation of macro-sized cracks in our earlie r works. The samples were evaluated by measuring the residual magnetic flux density after field-cooling the samples. The trapped-field distributions m apped at 77 K show that samples with 10 or more wt.% Ag2O consist of a sing le domain with no severe weak-links. The trapped magnetic flux density at t he open surface of a sample with 20 wt.% Ag2O and 30 mm in diameter was 8.0 T at 40 K. It was also found that the addition of Ag affects the microstru cture of the sample and the distribution of the Sm2BaCuO5 phase was more ho mogeneous in samples with larger amount of Ag.