Critical Currents of Tl₂Ba₂Ca₂Cu₃O_z Bulk Superconductors

Abstract

The critical temperatures and the critical currents of Tl2Ba2Ca2Cu3Oz (Tl-2223) bulk superconductor have been studied using ac susceptibility measurements before and after the oxygenation process. With oxygenation the critical temperature increased from 114.2 K to 118.8 K and the critical current at 77 K raised from 56 A/cm 2 to 230 A/cm 2. The Ginzburg-Landau strong coupling limit approach was applied to describe the temperature dependence of the critical current densities.