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The polycrystalline BiPbSrCaCu MO, with M = Zr ( x = 0.0, 0.02, 0.04), were synthesized by solid-state reaction method and studied by X-ray diffraction analysis (XRD), scanning electron microscopy equipped with energy dispersive of X-ray analysis (SEM/EDX) and resistivity versus temperature measurements. The influence of the Zr addition on the Tc and microstructure properties of the superconducting compounds has been studied. SEM observations show whiskers grains randomly distributed and microstructural change due to the addition of Zr. The ZrO was incorporated into the crystalline structure of BSCCO system in all samples. The crystallographic structure remains in a tetragonal form where a= b≠ c. Generally, all samples exhibit semiconductor behaviour above $T_{\mathrm {c}}^{\text {onset}}$ . The onset critical temperature $T_{\mathrm {c}}^{\text {onset}}$ increases up to 86 with x = 0.02. There is an enhancement in the critical temperature for doped samples as compared with pure BiPbSrCaCuO.Changes in superconducting properties of ZrO nanoparticle added Bi-2212 system were discussed. [ABSTRACT FROM AUTHOR]

In this work we present a systematic study of the Mn influence superconducting properties. Attempts have been made to identify the optimum inclusion of MnO in BiSrCaCuO superconductors. The phase formation, texture and grain alignments were analysed by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry (SEM, EDS) and electrical resistivity. It was found that Mn addition has affected the formation of the desired Bi-2212 phase and the microstructure of these samples thereby influencing on the resistivity. The resistivity of all the BiSrMnCaCuO samples shows metallic behaviour. It reveals that, 4 wt% composite exhibits a better superconducting property in comparison with pure BSCCO. It has been observed that Mn residing at the grain boundary of BSCCO matrix influences the tailing region with having significant change in the critical temperature. The microstructures observed by SEM indicate segregation of an additional phase. The EDS revealed that this phase is stoichiometric. The results show that the doping leads to a reduction of cell volume as well as the c axis. [ABSTRACT FROM AUTHOR]

The effects of the BCO addition on the formation and properties of the Bi-based superconductors were studied. Phase identification, and structural and microstructural analyses were carried out using the powder X-ray diffraction method (XRD), scanning electron microscopy (SEM/EDX), AC magnetic susceptibility and resistivity measurements. The experiment results showed an increase of the superconducting phase content (BCO) with x=0.01 and all samples doped with B contain the 2212 phase. In the BCO added samples (with x=0.01), the c lattice parameter decreased slightly from the nonadded sample showing the possibility of B incorporating into the crystal structure of the Bi-2212 phase. The variation in cell parameters is due to the difference in the ionic radii of B (0.2 Å) and Ca (1.06 Å). The SEM observation showed whisker grains, which are randomly distributed. The microstructural change is due to the addition of B. From the resistivity measurement, the $T_{\mathrm{c}}^{\mathrm{onset}}$ was found to be increased by 4 K for the doped sample compared to the undoped sample. An improvement of the normal state conductivity is obtained with a small amount of the addition (0.01). In the normal state, all the samples exhibit a metallic behavior. [ABSTRACT FROM AUTHOR]

The influence of zirconium (Zr) addition to the BiSrCaCuO (Bi2212) system on its phase formation, microstructure, transport, and magnetic properties is investigated. Samples have been characterized by means of X-ray diffraction analysis (XRD), scanning electron microscopy equipped with energy dispersive of X-ray analysis (SEM/EDX), and resistivity versus temperature measurement. The results show an increase of the critical temperature of superconductive transition T for x=0.01 and in all the samples containing Zr the Bi2212 phase is the majority. SEM observations show whiskers grains randomly distributed and microstructural change due to the addition of Zr. Resistivity measurement show that the temperature of the onset of transition T increases by 9 K for x=0.005, 0.02, and 5 K for x=0.01 of ZrO. An improvement of the normal state conductivity is obtained for the lowest content of Zr ( x=0.005). In the normal state, all the samples exhibit a metallic behavior except the sample with x=0.01, which exhibit a semiconductor character. [ABSTRACT FROM AUTHOR]