Critical current densities and irreversibility fields of high-Tc superconductors AuBa2Can-1CunO2n+3 (n=3, 4) prepared under high pressure

Critical current densities (J(c)) and irreversibility fields (B-irr) of high-T-c superconductors AuBa2Can-1CunO2n+3 [Au-12( n - 1)n, n = 3, 4] prepared under high pressure were determined from the hysteresis in DC magnetization loop. Both the J(c) and B-irr values of the Au-1234 phase were larger than those of Hg- and Bi-based cupurate superconductors, but smaller than those of the Y-123 superconductor. This result suggests that the electronic structure of Au-1234 is less anisotropic compared with the Hg- and Bi-phases. The Au-1223 phase showed very small J(c) values corresponding to its small superconducting volume fraction. (C) 2003 Elsevier Ltd. All rights reserved.