Synthesis, stability range and characterization of Pr₂Cu₂O₅

Abstract

A novel Pr₂Cu₂O₅ phase has been prepared under high-pressure and high-temperature conditions (P ∼6 GPa and T ∼1673 K) in a Belt-type apparatus and characterized by X-ray diffraction and electron microscopy. The crystal structure appears to be an orthorhombic “oxygen-deficient perovskite” (M.T. Anderson, J.T. Vaughey, and K.R. Poeppelmeier, Structural similarities among oxygen-deficient perovskites, Chem. Mater. 5 (1993), pp. 151–165) isostructural with La₂Cu₂O₅ (J.F. Bringley, B.A. Scott, S.J. La Placa, R.F. Boheme, T.M. Shaw, M.W. McElfresh, S.S. Trail, and D.E. Cox, Synthesis of the defect perovskite series LaCuO _3−δ with copper valence varying from 2+to 3+, Nature 347 (1990), pp. 263–265) and Nd₂Cu₂O₅ (B.-H. Chen, D. Walker, E. Suard, B.A. Scott, B. Mercey, M. Hervieu, and B. Raveau, High pressure synthesis of NdCuO_3−δ perovskites (0≤δ≤0.5). Inorg. Chem. 34 (1995), pp. 2077–2083).

Keywords:

• high pressure
• rare-earth cuprates
• oxides

Acknowledgements

The authors acknowledge the financial support from the Spanish Research Agency (CICYT, Project MAT2004-1641) and CAM (Materyener Project S-0505/PPQ-0093). We also thank Dr J.M. Gallardo-Amores for his help in the synthesis and Dr A. Dos Santos Garcĺıa, Elizabeth Castillo and Angel Arévalo for their valuable discussions. We also thank Dr Dave Rubie and Dr Dan Frost, Bayerisches Geoinstitut (Germany), for their comments and discussions.