Magnetic Properties of Partial Melt (Tl_0.5Pb_0.5) (Ba_xSr_0.8)₂Ca₂Cu₃O_y(x = 0.1,0.2) Superconductors

Magnetic measurements have been carried out on partial melt (Tl_0.5Pb_0.5)(Ba_xSr_0.8)₂Ca₂Cu₃O_y(x= 0.1,0.2) (TI-1223) samples, which indicate that higher melting temperature and longer melting time can be used to obtain Tl-1223 compound with better superconducting properties. On the contrary, introducing of Ba vacancy into Tl-1223 samples results in worse superconducting properties. At the end, the power law relationship between the critical current density and the applied field is explained by the flux creep model and the collective pinning theory.