Increasing critical temperature on BPSCCO superconductors with addition of Al2O3

We have investigated the effect of addition of Al₂O₃ in the manufacture of the BPSCCO superconductors using solid state reaction method. Precursors with consist of Bi₂O₃, PbO₂, SrCO₃, CaCO₃, and CuO powders were ground using mortar agate for 3 h. The samples were heated at 300°C for 6 h to remove the moisture in the powders, and then ground again for 6 h. Then the samples were calculated at 820°C for 20 h and then Al₂O₃ (1wt% and 2wt%) were added and ground again. The powders were compacted with a diameter of 10 mm and a thickness of 2 mm and then sintered at 850°C for 30 h. The characterizations were carried out by using Cryogenic Magnet to determine the superconductivity properties, SEM-EDX to analyze the morphology and XRD to determine the phase formed. The resistivity versus temperature results showed the increase of Tc with the addition of Al₂O₃. Sample with 1wt% Al₂O₃ has Tc_onset of 90 K and Tc_zero of 66 K, when the sample with 2wt% Al₂O₃ has Tc_onset of 94 K and Tc_zero of 73 K. The morphology formed looks less homogeneous, the crystalline granules are melt-shaped, clumpy and there are porosity. (paper)