Effects of Sb substitution on structural and superconducting properties of Bi in Bi1.75−xPb0.25SbxSr2Ca2Cu3Oy superconductor

In this work, we investigate the effects of Sb substitution on structural and superconducting properties of Bi 1.75−x Pb 0.25 Sb x Sr 2 Ca 2 Cu 3 O y superconductor for x = 0.00–0.20. Powder X-ray diffraction analysis showed that the samples consist of the Bi-2212 phase is dominant in all samples and the impurity phases was observed to increase with increasing the substitution ratio. Moreover, the intensity of the (115) peak for the low phase and the (117) peak of the high temperature phase decrease with increasing Sb substitution. The grain size, grain connectivity and surface morphology of the samples are identified from SEM microphotographs. Temperature dependence of resistivity revealed the highest Tc value at 110 K for x = 0.1 Sb substitution ratio. The density of all prepared samples were determined and was found to decrease with increasing Sb substitution, while porosity found to increase with increasing the substitution ratio.