SILVER-DOPING EFFECTS ON THE MULTIPLE-TRANSITION OF THE COMPLEX SUSCEPTIBILITY AND SUPERCONDUCTING PROPERTIES OF MELT-TEXTURED YBA2CU3OY MATERIALS

A series of textured (YBa2Cu3Oy)1-xAgx samples prepared by the melt-texture growth method have been investigated by analysis of the crystal structure, microstructure and composition, and by measurement of supercondUCtiVity, AC susceptibility and DC magnetization. A new multiple-transition of the complex susceptibility located at about 75, 60, 50 and 40 K, was observed by high-resolution AC susceptibility measurements. The pronounced inhomogeneous superconductivity is attributed to the inhomogeneous distribution of oxygen content in melt-texture grown (MTG) samples. The silver-doping effects on the multiple-transition, superconductivity, critical current density and irreversibility line have also been examined. Comprehensive analyses indicate that the silver-doping is beneficial to the penetration of the oxygen into the MTG materials, but has no significant effect on improving the flux pinning.