Effects of superconducting parameters of SnO₂ nanoparticles addition on (Bi, Pb)-2223 phase

Abstract

In this work, nano-SnO₂ (<100 nm) added samples in Bi_1.7−xPb_0.3Sn_xSr₂Ca₂Cu₃O_y (x = 0.00–0.20) were prepared by conventional solid-state reaction method. The phase formation, volume fraction and lattice parameters were characterized using X-ray powder diffraction measurements. Surface morphology and grain connectivity of the samples were identified by using scanning electron microscope (SEM). Diamagnetic onset temperatures (T ^on_c ) and hole concentration (p) of SnO₂ added samples were determined by ac susceptibiliy measurements. AC susceptibility measurements showed that diamagnetic onset temperatures (T ^on_c ) of samples Sn0 (x = 0.00), Sn1 (x = 0.05), Sn2 (x = 0.10), Sn3 (x = 0.15) and Sn4 (x = 0.20) are 108.559, 109.985, 101.281, 101.670 and 92.676 K, respectively. SEM measurements showed that not only the surface morphology and grain connectivity degrade but also the grain size of the samples decrease with the increase of the Sn addition. Also, addition of SnO₂ nanoparticles increases the impurities, voids and porosity. X-ray diffraction patterns of all samples indicated the majority of Bi-2223 and Bi-2212 phases along with minor impurity phase Ca₂PbO₄. The volume fraction of the Bi-2223 phase for the sample with x = 0.10 SnO₂ showed the highest percentage (49.49) and with further increasing SnO₂, the volume fraction of the Bi-2223 phase decreases and Bi-2212 phase increases. All SnO₂ nanoparticles added samples showed quite similar lattice parameters compared with non-added sample. These results indicate that nano SnO₂ does not have significant impact on the lattice parameters.