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

Critical current densities <f>(Jc)</f> and irreversibility fields <f>(Birr)</f> of high-<f>Tc</f> superconductors AuBa2Can−1CunO2n+3 [Au-12(n−1)n, <f>n=3,4</f>] prepared under high pressure were determined from the hysteresis in DC magnetization loop. Both the <f>Jc</f> and <f>Birr</f> 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 <f>Jc</f> values corresponding to its small superconducting volume fraction. [Copyright &y& Elsevier]