Crystal structure and superconductivity in La1.95Bi0.05CuO4+δ oxidized by a KMnO4 aqueous solution

✍ Scribed by Masatsune Kato; Hiroshi Chizawa; Yasuhiro Ono; Yoji Koike

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 605 KB
• Volume: 256
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(95)00473-4

✦ Synopsis

We have obtained Lal.9~Bio.osCuO4+ ~ with various values of 8 by the KMnO 4 oxidation method. The largest value of = 0.136 is about twice as large as that obtained by annealing under high pressures of oxygen, B = 0.056. A structural phase transition from the orthorhombic to the tetragonal phase with the increase of (5 is observed at 8 = 0.035-0.04. For 8 > 0.08, another orthorhombic phase with large orthorhombic distortion appears and forms a mixture with the tetragonal phase. Superconductivity appears in the range of 8 > 0.03. In the mixture range of 8 > 0.08, however, the orthorhombic phase may exhibit no superconductivity due to the overdoping of hole carders into the CuO 2 plane. The maximum Tc increases up to ~ 35 K, which is about 10 K higher than that obtained by annealing under high pressures of oxygen, owing to the larger hole concentration in the CuO 2 plane.