Résumé:
The purpose of the work of this thesis is to develop and characterize the structure and magnetic superconducting ceramic samples Bi2Sr2CaCu2O8+δ were prepared by the Sol-Gel method. These are superconducting ceramics based on bismuth with a polycrystalline shape. The influence of Ba by substitution in the Sr site was studied. The results obtained are performed and discussed by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with EDS. The critical transition temperatures Tc were determined by the susceptibility as a function of the temperature measurements. The results of DRX show the obtaining of the compound Bi2Sr2CaCu2O8+δ with the presence of the small peaks of the phase Bi2201 in Ba=0.02. From the calculation of the volume fraction that the dominant phase is Bi2212, with regard to the mesh parameters we use we find the software DICVOL04, these values(cell parameter) show that the structure of different samples is tetragonal. Scanning electron microscope (SEM) to show that the samples have long and plate shaped grains that characterize the lamel structure of the Bi2212 phase. EDS confirm the presence of dopant in each sample and show a uncontaminated synthesis process. Raman spectroscopy shows the increase of the B1g peak which indicates the possible substitution of Sr by Ba and Cu by Ba. The introduction of Ba in the Bi-2212 phase leads to a lower critical temperature and improved superconducting properties when the Ba content is low
