Ordered substitution of iron for copper in the tetragonal perovskite La{sub 6.4}Sr{sub 1.6}Cu{sub 8}O{sub 20}
- Universite de Caen (France)
Two series of iron-substituted cuprates with the tetragonal La{sub 6.4}Sr{sub 1.6}Cu{sub 8}O{sub 20} oxygen deficient perovskite structure have been isolated: La{sub 6.4}Sr{sub 1.6}Cu{sub 8-x}Fe{sub x}O{sub 20} (0 {le} x {le} 1.20) and La{sub 6.4-x}Sr{sub 1.6+x}Cu{sub 8-x}Fe{sub x}O{sub 20} (0 {le} x {le} 2). The XRD and Moessbauer studies show that they correspond to a preferential substitution of Fe(III) for copper in the octahedral sites of the structure. In fact the ideal structure can be described as 90{degrees}-oriented {open_quotes}123{close_quotes} copper ribbons interconnected with [FeO{sub 3}]{infinity} rows of FeO{sub 6} octahedra. The transport properties of these phases show a transition from a metallic to a semiconducting state. The difference in behavior between the La{sub 6.4}Sr{sub 1.6}Cu{sub 8-x}Fe{sub x}O{sub 20} series and the La{sub 6.4-x}Sr{sub 1.6+x}Cu{sub 8-x}Fe{sub x}O{sub 20} series is interpreted on the basis of hole carrier density introduced by Cu(III) and of the trapping of carriers by Fe(III) species. The possibility of anisotropic transport properties with a metallic conductivity along c is discussed.
- OSTI ID:
- 75773
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 115; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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