AC susceptibilities in Ag-based composites of Hg(Pb,Bi)-1223 superconductors

Compounds of the Hg1-xPbxBa2CaCu3O8+delta (x = 0.1 and 0.2) and Ag-y(HgBa1.9Bi0.1Ca2Cu3O8+delta)(1-y) (y = 0.1 and 0.2) were synthesized directly from the metal oxides without using a precursor. The structural and morphological properties were investigated. AC susceptibilities and DC magnetizations were measured using a SQUID magnetometer and a PPMS susceptometer. From the magnetic data, the critical temperatures are 134 K in Hg(Pb)1223 composites and 131 K in Ag-Hg1223. The estimated superconducting volume in the Ag-Hg1223 reduces when Ag content increases. AC losses estimated from the imaginary part of the AC susceptibilities X" and pinning potentials evaluated from the relaxation rate of the magnetization are compared and discussed in both samples. (C) 2003 Elsevier Science B.V. All rights reserved.