AC SUSCEPTIBILITY IN Y123 AND AG-DOPED Y123 COMPOUNDS PREPARED BY THEMELT-TEXTURED-GROWTH METHOD

Bulk Y123 and Y123 + 4.5wt.% Ag samples with high J(c) were prepared b y a melt-textured-growth process. AC susceptibility measurements have been carried out and the temperature dependence of chi'' in these mate rials is presented. The results show that the ''peak temperature'' T(p ) of chi''(T) shifts to lower temperatures as the AC field amplitude ( h(AC)) is increased. The slopes of the T(p)-h(AC)2/3 lines for h(AC) p arallel to the c-axis are larger than those with h(AC) perpendicular t o the c-axis. We believe that the higher slope corresponds to a strong intergranular coupling. The presence of silver has no effect on the c oupling in the a-b plane of the material, but is found to enhance the coupling parallel to the c-axis direction.