Preparation ofLa1.29Ca0.43Ba1.29Cu3Oy powder with different organic acids containing OH or NH2

摘要

More than ten organic acids containing hydroxyl or amino groups were selected as a medium to prepare submicrometer superconducting powder of La1.29Ca0.43Ba1.29Cu3 Oy by using a polymeric precursor method. Heat treated samples were analyzed by IR spectrometer for the degree of polymerization, by ICP and EDS for the homogeneity, by SEM for the particle size determination. Tc measurement and the purity examination were obtained by resistivity and X-ray diffraction, respectively. Organic acids containing three carboxyl groups are highly recommended for preparing high-Tc superconductors. It donates electron pairs for chelating with metal ions and also for the polyesterification with ethylene glycol. On the other hand, organic acids containing amino group along with two or less carboxyl acid groups are not recommended for this purpose