Intergranular properties of (Y1-x-yZrxCay)Ba2Cu3O7-delta compounds

The intergranular properties of (Y1 - x - yZrxCay)Ba2Cu3O7 - delta ceramics were studies by using temperature-dependent ac susceptibility measurements at zero de magnetic field. The intergranular critical current density was determined from ac susceptibility data by varying the field amplitude H-ac. From the imaginary part of the complex susceptibility, chi "(T), we have d etermined the temperature dependence of the critical current density by usi ng the Bean's model. The ac field dependencies of the intergrain chi "-peak temperatures T-P are linear and agree with Muller critical state model. Th e results were analyzed in terms of superconductor-insulator-superconductor (SIS)-and superconductor-normal-superconductor (SNS)-type models for granu lar superconductors.