AC susceptibility and intergranular critical current density study in pure and Ag doped (La1-xYx)(2)Ba2CaCu5Oz superconductors

摘要

The temperature and AC field amplitude variations of AC susceptibility have been measured on pure and 5 wt% Ag doped (La1-xYx)(2)Ba2CaCuOz superconductors. The AC susceptibility as a function of field have been analyzed using Kim's critical state model. The temperature dependence of intergranular critical current density and the effective volume fractions of the grains have been estimated. The Ag doped samples show relatively large critical current density due to the improved intergranular coupling. The exponent of temperature variation of critical current density suggests that the weak links form superconductor-normal metal-superconductor (SNS) type of junctions for all the samples. (c) 2006 Elsevier Ltd. All rights reserved.