Effect of high Ag mixing on pinning properties in Hg-1223 superconductors

摘要

Ag-added composites of Hg-based Ag-x(HgBa1.9Bi0.1Ca3Cu3O8+delta)(1-x) superconductor were prepared by direct synthesis from the oxide powders. Since Ag-addition of x - 0.1 and 0.2 was confirmed to increase the uniformity of the sample quality and to enhance the connectivity between the grain, we fabricated high mixed samples with Ag content x = 0.3 and 0.4 and investigated the effect on superconducting properties. The structural and morphological properties were investigated. The estimated superconducting volume reduces drastically comparing with the former samples with low x. Magnetization width is large in low Ag content x = 0.1 and 0.2 and small in x = 0.3 and 0.4 at low temperatures. Excess Ag mixing over x = 0.3 leads a deterioration of Hg-1223 phase nucleation and begins to decrease the pinning properties. Campbell penetration depths lambda(0)' estimated from the AC susceptibility plane indicates a rapid increase near the critical temperature. Ag-addition tends to enhance the connectivity between the grains. (C) 2004 Elsevier B.V. All rights reserved.