Terbium-neodymium co-doping in Bi sites on the BPSCCO bismuth cuprate superconductor

The parent BiPbSr2Ca2Cu3O10 (BPSCCO) and samples of the general formula Bi1-(x+y)NdxTbyPbSr2Ca2Cu3O10, where x = y = 0.05, 0.1 and 0.2, were prepared using the conventional high-temperature solid-state reaction technique. The superconducting measurements proved that the best value of Tc, 108 K, is for the sample with x = y = 0.1 mol% while the lowest value of Tc, 101 K, is for the sample with maximum dopant concentration x = y = 0.2 mol%. The evaluated crystalline lattice structure of the prepared samples mainly belongs to the superconductive tetragonal phase (2223) besides the secondary (2212) phase. Also, thermogravimetric and differential thermal analyses were studied on the green mixture showing an endothermic peak at 790 °C corresponding to the superconductive phase formation. The microstructures of the prepared samples were investigated by scanning electron microscopy and energy dispersive x-ray analysis.