ALKALINE DOPED BI-PB-(SB)-SR-CA-CU-O SUPERCONDUCTING MATERIALS

The effect of all alkali elements on the phase composition and superco nducting properties of Bi1.6Pb0.3Sb0.1Sr2Ca2Cu3Mx+Oy and Bi1.6Pb0.3Sb0 .1Sr2Ca2Cu3-xMx+Oy (M+ = Li, Na, K, Rb, Cs; x = 0.3, 0.5, 0.8) materia ls was investigated. A correlation was found between the atomic weight of the alkaline dopants and the formation of the 2-2-2-3 phase. It wa s also established that the 2-2-2-3 phase is promoted when the alkali metals are introduced as additives, but not replacing the Cu in the in itial composition. The analysis of the chemical composition of synthes ized materials showed that the final concentration of the dopants is n egligible (for the case of Li, Na or K) or even undetectable (for Rb a nd Cs).