حسین نیک منش

The influence of using two different starting materials (nitrates and carbonates) and calcination processes on the grain boundary properties of a BSCCO system have been investigated. Superconducting BSCCO samples with the chemical composition Bi1.64Pb0.34Sr2Ca2Cu3Oy were successfully fabricated by the sol–gel method. X-ray diffraction (XRD) and scanning electron microscopy analyses have been used to study the phase formation and microstructure of the prepared samples, respectively. The DC electrical resistivity, critical current density, and AC susceptibility of the samples were measured. The XRD result showed that one can improve the phase formation of the Bi-2223 system by choosing suitable starting materials and the temperature of calcination. AC susceptibility and DC electrical resistivity revealed that the synthesis process improves the grain boundaries. The critical current density (measured in 77 K) increased from 100 A cm?2 to about 145 A cm?2. In fact, the critical current of the sample fabricated with a carbonates group and calcinated at 750 °C obtained 100 A cm?2, while a sample that was fabricated with a nitrates group and calcinated at 790 °C had the critical current of 145 A cm?2.