Structure and magnetism of 4H-BaMnO{sub 3-x} (0=<x=<0.35) and 4H-Ba{sub 0.5}Sr{sub 0.5}MnO{sub 3-x} (0=<x=<0.21)

Journal Article · Sun Jan 15 04:00:00 EST 2006 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.09.046· OSTI ID:20784832

Adkin, Josephine J ^[1]; Hayward, Michael A ^[1]

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1. Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR (United Kingdom)

The synthesis and structure determination of 4H-BaMnO{sub 3-x} (0=<x=<0.35) and 4H-Ba{sub 0.5}Sr{sub 0.5}MnO{sub 3-x} (0=<x=<0.21) is described. Neutron powder diffraction data unambiguously show the anion vacancies in the oxygen-deficient phases lie in the hexagonal BaO{sub 3-x} layers, rather than the cubic layers predicted by previous structural models. The localization of anion vacancies in the hexagonal layers is discussed on the basis of the local co-ordination polyhedra of the metal cations. Low-temperature neutron diffraction data show the oxidized materials adopt antiferromagnetic ordered structures (Ba{sub 0.5}Sr{sub 0.5}MnO{sub 2.99}: T{sub N}=265K). Anion-deficient phases do not achieve magnetic order suggesting the Mn(III/IV) charge disorder suppresses long-range magnetic order.

• OSTI ID: 20784832
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 1 Vol. 179; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANIONS
ANTIFERROMAGNETISM
BARIUM COMPOUNDS
CATIONS
LAYERS
MANGANESE COMPOUNDS
NEUTRON DIFFRACTION
OXIDES
PEROVSKITE
STRONTIUM COMPOUNDS
STRUCTURAL MODELS
SYNTHESIS
VACANCIES