EFFECT OF LITHIUM DOPING IN THE BI-2212 SUPERCONDUCTING SYSTEM

Samples with the nominal composition Bi2Sr2Ca1-xLixCu2Oy (x = 0.2, 0.4, and 0.6) and Bi2Sr2CaCu2-x.Li(x)Q(z) (x = 0.4, 0.6, and 1.0) were prepared by the solid state reaction method. The role of Li at both Ca- and Cu sites in the Bi-2212 composition were studied. From the X-ray diffraction data it was found that the Li-doped at the Ca site increases the c-axis and that doped at the Cu site decreases the c-axis. From the D.C. four-probe resistivity data it was found that Li-doped at the Ca site reduces the T-c and the Li-doped at the Cu site gives T-c(0) above the liquid nitrogen temperature. It was observed that the Li doping reduces the melting point of Bi-2212 composition. The presence of Lithium was confirmed by inductive the coupled plasma method.