par Duvigneaud, Paul-Henri 
;De Boeck, Christian ;Guo, Yufen Y.F.
Référence Superconductor science and technology, 11, 1, page (116-121)
Publication Publié, 1998-01
;De Boeck, Christian ;Guo, Yufen Y.F.Référence Superconductor science and technology, 11, 1, page (116-121)
Publication Publié, 1998-01
Article révisé par les pairs
| Résumé : | Samples with Bi2.05Sr1.9Ca1.05Cu2O 8+δ composition were synthesized by an original process based on the spray drying of a nitrate solution of Bi, Sr, Ca and Cu cations complexed with EDTA at pH >6. After calcination at 800°C and grinding, the samples were sintered in the range 820-860°C in air and annealed between 600°C and 700°C in nitrogen. The relationships between critical temperature (Tcon and Tcoff), Bi and Cu valences (determined by permanganate and iodometric titration) and cell parameter c were investigated. The relatively weak variation of Bi with respect to that of Cu as a function of the oxygen excess δ in the BiO planes provides evidence for a 'buffer' effect in these planes induced by the charge transfer from the CuO2 planes. |
