EFFECTS OF SILVER AND Y2BACUO5 INCLUSIONS ON THE TRANSPORT CURRENT-DENSITY AND ITS ANISOTROPY OF ORIENTED-GRAINED YBA2CU3OX SILVER COMPOSITES

Transport critical current density (J(ct)) measurements were performed on bulk oriented-grained YBa2Cu3Ox/Silver composites in the presence of a magnetic field (B). J(ct) of these composites exhibit strong anisotropic behavior when the angle between the applied field and the c-axis of the specimen is varied. Two J(ct) peaks were observed; a sharp peak centered at B perpendicular to the c-axis and a J(ct) value roughly 3 times higher than that of the minimum J(ct) is found. Another broader and weaker peak is found to be centered at B parallel to the c-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 on J(ct) were also investigated. Relatively small amount of randomly distributed normal-phase particles are found to have negligible effect on the (J(ct) anisotropy. The large Ag inclusions are determined to be ineffective pinning centers and J(ct) decreases with Ag content. The 0.5 to 2 mum size 2-1-1 additions, however, appear to enhance the J(ct) of the composites.