A new manganite with an original composite tunnel structure: Ba{sub 6}Mn{sub 24}O{sub 48}

Journal Article · Mon Sep 01 04:00:00 EDT 1997 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1997.7412· OSTI ID:569678

Boullay, Ph; Hervieu, M; Raveau, B ^[1]

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1. Universite de Caen (France)

A new manganite Ba{sub 6}Mn{sub 24}O{sub 48} with an original tunnel structure has been synthesized. Its electron diffraction study shows that this new phase exhibits a composite structure, built up of two tetragonal I sublattices with a = 18.2 {angstrom}, c{sub 1} = 2.8 {angstrom}, and c{sub 2} = 4.6 {angstrom}. The high-resolution electron microscopy investigation shows that the octahedral [Mn{sub 4}O{sub 8}]{sub {infinity}} host lattice consists of hollandite- and rutile-type columns sharing the edges of their MnO{sub 6} octahedra so that a new kind of ten-sided tunnel is generated. The powder X-ray diffraction study confirms that the first sublattice (a, c{sub 1}) corresponds to the [Mn{sub 4}O{sub 8}]{sub {infinity}} framework. The second sublattice (a, c{sub 2}) is associated with the barium network. The incommensurate modulated superstructural spots in the {open_quotes}a, c{sub 2}{close_quotes} sublattice are correlated to both the occupancy and displacive modulation of the barium ions in the two kinds of tunnels.

• OSTI ID: 569678
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 132; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
BARIUM OXIDES
CRYSTAL LATTICES
ELECTRON DIFFRACTION
ELECTRON MICROSCOPY
MANGANESE OXIDES
RUTILE
X-RAY DIFFRACTION