MAGNETIC-PROPERTIES OF PARTIAL MELT (TL0.5PB0.5) (BAXSR0.8)(2)CA2CU3OY (X=0.1,0.2) SUPERCONDUCTORS

Magnetic measurements have been carried out on partial melt (Tl0.5Pb0. 5)(BaxSr0.8)(2) Ca2Cu3Oy (x = 0.1, 0.2) (Tl-1223) samples, which indic ate that higher melting temperature and longer melting time can be use d to obtain Tl-1223 compound with better superconducting properties. O n the contrary, introducing of Ba vacancy into Tl-1223 samples results in worse superconducting properties. At the end, the power law relati onship between the critical current density and the applied field is e xplained by the flux creep model and the collective pinning theory.