錯体重合法による超伝導体の合成と物性 (酸化物超伝導体の材料プロセスと特性評価<特集>)

概要

論文の詳細を見る
A novel "polymerized complex" technique to produce highly pure copper based high-Tc superconductors has been developped. The method is based on the formation of a plymer metal complex precursor which is prepared through polyesterification between metal citrate complexes and ethyleneglucol. The general idea of this technique is to have a polymer complex with various metal ions, which are uniformly distributed in the polymer network keeping the initial stoichiometric ratio. Heating of the polymer metal complex precursor at high temperature brings about a breakdown of the polymer, which may allow to construct lattices of ceramics oxides directly. It is then assumed in this study that low cation mobility in the highly viscous polymer network causes only little segregation of the various metal ions during the pyrolysis. A particular attention was paid on the phase purity of the product, and the single-phase character of the final product was confirmed by the combined results of X-ray diffraction, Raman scattering and complex magnetic susceptibility measurements.. The present paper highlights the advantages of the polymerized complex technique in the synthesis of copper-based ceramic superconductors. Emphasis is placed to outstanding purity of the product as is revealed by superconducting transition widths much sharper than those for ceramic samples previously reported synthesis procedures.
社団法人粉体粉末冶金協会の論文