Effects of Silver and Y2BaCuO5Inclusions on the Transport Current Density and its Anisotropy of Oriented-Grained YBa2Cu3Ox/Silver Composites

Abstract
Transport critical current density (Jct) measurements were performed on bulk oriented-grained YBa2Cu3Ox/Silver composites in the presence of a magnetic field (B).Jctof these composites exhibit strong anisotropic behavior when the angle between the applied field and thec-axis of the specimen is varied. TwoJctpeaks were observed; a sharp peak centered atBperpendicular to thec-axis and aJctvalue roughly 3 times higher than that of the minimumJctis found. Another broader and weaker peak is found to be centered atBparallel to thec-axis. This anisotropic behavior is detected at all field strengths investigated at 77 K. The effects of Ag as well as Y2BaCuO5(2-1-1) additions onJctwere also investigated. Relatively small amount of randomly distributed normal-phase particles are found to have negligible effect on theJctanisotropy. The large Ag inclusions are determined to be ineffective pinning centers andJctdecreases with Ag content. The 0.5 to 2 µm size 2-1-1 additions, however, appear to enhance theJctof the composites.