Effect of silver addition on the field trapping properties of Gd–Ba–Cu–O bulk superconductors

Abstract

The effect of Ag addition on the field trapping properties of Gd–Ba–Cu–O bulk samples has been studied. Gd–Ba–Cu–O bulk superconductors 32 mm in diameter were melt textured by varying the amount of Ag 2O in the range of 0–30 wt.%. The trapped magnetic field of Ag-free bulk sample was 1.3 T at 77 K. This value could be improved to 1.8–2.0 T with Ag addition of 10–20 wt.%. A further increase in Ag 2O content degraded the field trapping ability. Ag-free bulk Gd–Ba–Cu–O exhibited the trapped field of 3.0 T at 65 K, however, the bulk was fractured at lower temperature. On the other hand, Ag-added bulk Gd–Ba–Cu–O exhibited the high trapped field value of 6.7 T at 55 K. These results indicate that the mechanical strength of the bulk Gd–Ba–Cu–O could be improved with Ag addition.