CHARACTERISTICS OF SUPERCONDUCTING YBCO PHASE FORMATION THROUGH AUTO COMBUSTION CITRATE-NITRATE SOL-GEL

摘要

Fine YBa2Cu3O_(7-δ) (YBCO) powder was synthesized through a sol-gel auto-combustion technique, in which nitrates were used as an oxidizing agent, and citric acid as an organic fuel/chelating agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric and differential thermogravimetric analyses (TGA/DTG) were employed to characterize the superconducting phase formation. The results show that the formation of YBa2Cu3O_(7-δ) phase is completed at 750-770 "C. Also the SEM photograph at a high magnification illustrates that the preferred mechanism of crystal growth is a spiral type.