Effect of doping Ba, Y V, Zn and Sn on BSCCO superconducting ceramics

The effect of doping on the superconductivity in Bi₂Pb _0.6Sr₂Ca_2-xR_xCu₃O _δ (R=Ba,Y,V,Zn,Sn) has been investigated by resistivity, ac susceptibility measurements and x-ray diffraction (XRD) analysis. All the dopants were incorporated in the calcium site with x ranging from 0.00 to 0.10. The temperature dependence of electrical resistance and ac susceptibility measurements was studied for these samples. The nature of the temperature dependence of the resistance curves indicates the presence of a superconducting transition between grains coupled by weak links. From the XRD data, it is observed that the volume percentage of the 2223 phase decreases with the increasing doping concentration. The presence of low T_c phase is also visible in the real component (χ\´), of the susceptibility data, while the imaginary component (χ"), shows a shift towards lower temperature in the intergranular coupling peak, T_p, as the dopant concentration increases. All the doping elements do not enhance the T _c zero but decreases its value from ~104 K to 88 K, 53 K, 79.6 K, 58 K and 53 K for Ba, Y, V, Zn and Y respectively for x=0.10. Barium doped samples are least affected by compositional variation and the zero resistance values are higher than that of the other doped samples