Irreversibility Curve on Y_1–xLu_xBa₂Cu₃O_7–δ (x=0.4, 0.5 and 0.6) superconducting

The irreversibility line in the H–T plane divides the irreversible and reversible behaviour of the magnetization which is of importance for the characterization of high T_c superconductors. In this work, we report the production of Y_1–XLu_XBa₂Cu₃O_7–δ (X=0.4, 0.5 and 0.6) superconducting system using the usual solid state reaction method. The irreversibility line H–T plane for the Y_1–XLu_XBa₂Cu₃O_7–δ polycrystalline sample was investigated. The curves of magnetization ZFC (cero field cooled)- FC (field cooled) were measured in magnetic fields between 100 Oe and 4000 Oe, and allowed to obtain the values for irreversibility and critical temperatures