Effect Of Zn Doping In Bi(Pb)-2212 Superconducting Ceramics

The subject of substitution in the high-T-c superconductors has received a great deal of interest. Substitution of bismuth by lead stabilizes and purifies the superconducting phase in Bi2223 and enhances T-c in Bi2212 [1-5]. The substitution of Cu by magnetic or non magnetic element such as Fe, Ni, Co or Zn degrades significantly T-c [6, 7]. The substitution by Zn is difficult because the amount that can be dissolved is limited. Samples of Bi1.6Pb0.4Sr2CaCu2-yZnyO8+d (0 <= y <= 0. 06) were prepared by a solid-state reaction method. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and AC susceptibility versus temperature measurements. Structural analysis shows that the obtained crystalline structure is mainly tetragonal with a c-axis lattice parameter decreasing with Zn content. AC susceptibility measurements show that the Zn doping decreases the superconducting volume fraction in the samples. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.