Synthesis and characterization of La{sub 1+x}Sr{sub 2-x}CoMnO{sub 7-{delta}}(x=0,0.2; {delta}=0,1)

Journal Article · Tue Jun 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.04.018· OSTI ID:21421521

El Shinawi, H ^[1]; Bertha, A; Hadermann, J ^[2]; Herranz, T; Santos, B; Marco, J F ^[3]; Berry, F J ^[1]; Greaves, C ^[1]

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1. School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom)
2. EMAT, RUCA, Groenenborgerlaan 171, Antwerp 2020 (Belgium)
3. Instituto de Quimica-Fisica 'Rocasolano', Serrano 119, CSIC, 28006 Madrid (Spain)

The n=2 Ruddlesden-Popper phases LaSr{sub 2}CoMnO{sub 7} and La{sub 1.2}Sr{sub 1.8}CoMnO{sub 7} have been synthesized by a sol-gel method. The O6-type phases LaSr{sub 2}CoMnO{sub 6} and La{sub 1.2}Sr{sub 1.8}CoMnO{sub 6} were produced by reduction of the O7 phases under a hydrogen atmosphere. The materials crystallize in the tetragonal I4/mmm space group with no evidence of long-range cation order in the neutron and electron diffraction data. Oxygen vacancies in the reduced materials are located primarily at the common apex of the double perovskite layers giving rise to square pyramidal coordination around cobalt and manganese ions. The oxidation states Co{sup 3+}/Mn{sup 4+} and Co{sup 2+}/Mn{sup 3+} predominate in the as-prepared and reduced materials, respectively. The materials are spin glasses at low temperature and the dominant magnetic interactions change from ferro- to antiferromagnetic following reduction. - Graphical abstract: The n=2 Ruddlesden-Popper phases LaSr{sub 2}CoMnO{sub 7}, La{sub 1.2}Sr{sub 1.8}CoMnO{sub 7}, LaSr{sub 2}CoMnO{sub 6} and La{sub 1.2}Sr{sub 1.8}CoMnO{sub 6} are synthesized and characterized.

• OSTI ID: 21421521
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 6; Other Information: DOI: 10.1016/j.jssc.2010.04.018; PII: S0022-4596(10)00151-9; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANTIFERROMAGNETISM
COBALT COMPOUNDS
COBALT IONS
ELECTRON DIFFRACTION
LANTHANUM COMPOUNDS
MANGANESE COMPOUNDS
MANGANESE IONS
NEUTRON DIFFRACTION
OXIDES
PEROVSKITE
SOL-GEL PROCESS
SPACE GROUPS
SPIN GLASS STATE
STRONTIUM COMPOUNDS
SYNTHESIS
TETRAGONAL LATTICES
VACANCIES
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
IONS
MAGNETISM
MINERALS
OXIDE MINERALS
OXYGEN COMPOUNDS
PEROVSKITES
POINT DEFECTS
RARE EARTH COMPOUNDS
SCATTERING
SYMMETRY GROUPS
TRANSITION ELEMENT COMPOUNDS