Comparison of the Irreversibility Line between Magnetization and Magnetoresistance Measurement for Nd-Ba-Cu-O Crystals

摘要

Magnetoresistance measurements were performed to investigate the irreversibility lines in the B-T diagram for an oxygen-controlled-melt-growth (OCMG) processed Nd-Ba-Cu-O bulk superconductor which exhibits the fishtail peaks in the magnetization hysteresis (M-H) curves. The location of the irreversibility line is dependent on the measuring method and is in the order: d.c. magnetization reversible onset < a.c. out-of-phase X_1"(T) maximum < zero magnetoresistivity. Sich difference is explained in terms of the criteria for the critical current density and the electric field.