MAGNETIC-BEHAVIOR OF WEAK LINKS IN BULK SUPERCONDUCTING YBA2CU3O7-X-AG COMPOSITE

The magnetization of a polycrystalline composite YBa2Cu3O7-x: Ag0.1 in the superconducting state is measured in the presence of a small a.c. magnetic field. With increase in field amplitude, the magnetization M(t) changes its shape from nearly sinusoidal to square-wave like and then to a two-peak structure. A similar behavior of the magnetization M(t), calculated from the critical-state model with intergranular critical current J(c) = ac[mu (H0 + \H\)]-1, is obtained. A very good fit is found between the theoretical and experimental results, and the parameters of the model are estimated.