Structural properties of (Pb,Cu) (Sr,Nd)2(Ho,Ce)2Cu2O9−δ

✍ Scribed by Toshihiko Maeda; Naomichi Sakai; Fujio Izumi; Takahiro Wada; H. Yamauchi; Hajime Asano; Shoji Tanaka

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 820 KB
• Volume: 193
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(92)90871-9

✦ Synopsis

Pb,Cu) (Sr,Nd)2(Ho,Ce)2Cu20.. (z~ 8.64) was made superconducting by heating at 500°C in 02 at a pressure of 90 atm. This oxide had a transition temperature (Tc) around 10 K. Its structure parameters were refined by the Rietveld method using neutron powder diffraction data. This compound belongs to space group 14/mmm and has a tetragonal unit cell with lattice constants, a = 0.382496 (8) nm and c= 2.89862 (7) nm. Atoms in fluorite-type layers and CuO2 planes are firmly bound at their ideal positions, whereas a (Pb,Cu)O monolayer is highly disordered and defective. In addition, an apical oxygen site in a [ CuOs ] pyramid is about 13% deficient. Such lattice instability in this oxide is discussed in connection with structural defects in other copper oxides.