Synthesis of oxide superconductors by soft-chemical techniques

✍ Scribed by Masatsune Kato; Yoshinori Imai; Tetsuya Kajita; Yuichiro Takarabe; Takefumi Minakawa; Ken-ichi Nemoto; Hiroto Tezuka; Takashi Noji; Yoji Koike

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 368 KB
• Volume: 148
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/j.mseb.2007.09.031

✦ Synopsis

Our recent works on the synthesis of oxide superconductors using soft-chemical techniques are reviewed. First, Li-intercalation into layered perovskites has been carried out. We have found new Li-intercalated superconductors of the Ruddlesden-Popper phase of Li x Sr 2 CuO 2 X 2 (X = Br, I) with T c = 7-8 K and the Dion-Jacobson phase of Li x ASr 2 Nb 3 O 10 (A = Rb, Cs) with T c ∼6 K. However, no superconductivity has appeared in Aurivillius phases of Li x Bi 4 Ti 3 O 10 and Li x Bi 2 MO 6 (M = Mo, W). Next, we have succeeded in preparing insulating La 2 CuO 4 with the Nd 2 CuO 4 -type (T ) structure and superconducting Ba 0.6 K 0.4 BiO 3 by the direct precipitation from molten alkaline-metal hydroxides at a temperature as low as 260-350 • C.