THE IRREVERSIBILITY LINE OF THE SUPERCONDUCTING COMPOUND HGBA2CA3CU4O10+DELTA

DC magnetization measurements were performed on the mercury-based supe rconductor HgBa2Ca3Cu4O10+delta. The analysis of the magnetic hysteret ic behavior of the sample either with temperature or with field, allow ed the determination of the irreversibility line of this compound, as well as temperature and magnetic field dependence of the critical curr ent density. The experimental temperature dependence of the irreversib ility field (H) is well described in terms of the reduced temperature by Hproportional to(1-T/Tc)(n), with 4.5<n<5.