Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S4MI, Canada
Abstract:
X-ray powder diffraction, magnetic susceptibility and electrical resistivity measurements have been used to investigate the effect of Sn substitution in the Bi1.7Pb0.3Sr2Ca2(Cu3−xSnx1.2Oy system for different values of Sn concentrationx(0×1.33). The substitution of Sn is found to decrease the superconducting volume fraction of the 2223 phase. The 2212 phase is enhanced until it reaches a maximum at x=0.67. The system has a complete 2212 phase at x=0.88. An increase in the normal-state resistivity with a corresponding suppression of the temperature at which the resistivity goes to zero is observed with increasing x for the samples which are superconducting. The substitution of Sn probably causes a spatial disorder in the CuO2 planes, which in turn enhances the Coulomb interaction. Samples with x1.0 are found to be insulating.