par De Boeck, Christian 
;Ciurchea, Decebal ;Duvigneaud, Paul-Henri
Référence Journal of the European Ceramic Society, 19, 6-7, page (1537-1541)
Publication Publié, 1999-06
;Ciurchea, Decebal ;Duvigneaud, Paul-Henri Référence Journal of the European Ceramic Society, 19, 6-7, page (1537-1541)
Publication Publié, 1999-06
Article révisé par les pairs
| Résumé : | Samples with Bi2·05Sr1·9Ca1·05(Cu 1-xFex)2O 8+δ(0≤x≤0·15) compositions were synthesized by a liquid-mix process able to give single phase compounds. The superconducting phase was carefully investigated by SEM and EDX. Substitution of x Fe atoms in the Bi2Sr2CaCu2O8+δ grains corresponds to the removal of 1·7x Cu atoms and to the addition of 0·75x Bi atoms whereas the sum Sr+Ca remains quite constant. In a first step, this evolution may be explained by the following basic model: Fe2O3→2Fecu•+V cu″+3 CuO which assumes the creation of vacancies in the copper sites of the Bi2Sr2CaCu2O8+δ lattice. However, the apparent increase of Bi content suggests the formation of microdomains of Bi2Sr2CuO6 phase intergrown in the Bi2·05Sr1·9Ca1·05(Cu 1-xFex)2O8+δ grains, as inferred from X-ray diffraction and SEM which reveals the concomitant (SrCa)14Cu24O41 secondary phase. The EDX results are more consistent with a Bi2Sr2CuO6-Bi2Sr 2CaCu2O8+δ intergrowth model in which Fe is accommodated in the Bi2Sr2CuO6 microdomains than with the model of substitution in a Bi2Sr2CaCu2O8+δ single phase. |
