Synthesis and characterization of La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}M{sub 0.5}O{sub 4-{delta}} (M=Fe, Mn)

Journal Article · Sat Aug 15 04:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.06.010· OSTI ID:21370549

El Shinawi, H ^[1]; Marco, J F ^[2]; Berry, F J ^[1]; Greaves, C ^[1]

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1. School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom)
2. Instituto de Quimica-Fisica 'Rocasolano', Consejo Superior de Investigaciones Cientificas, Serrano 119, 28006 Madrid (Spain)

The M{sup 4+}-containing K{sub 2}NiF{sub 4}-type phases La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Fe{sub 0.5}O{sub 4} and La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 4} have been synthesized by a sol-gel procedure and characterized by X-ray powder diffraction, thermal analysis, neutron powder diffraction and Moessbauer spectroscopy. Oxide ion vacancies are created in these materials via reduction of M{sup 4+} to M{sup 3+} and of Co{sup 3+} to Co{sup 2+}. The vacancies are confined to the equatorial planes of the K{sub 2}NiF{sub 4}-type structure. A partial reduction of Mn{sup 3+} to Mn{sup 2+} also occurs to achieve the oxygen stoichiometry in La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 3.6}. La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Fe{sub 0.5}O{sub 3.65} contains Co{sup 2+} and Fe{sup 3+} ions which interact antiferromagnetically and result in noncollinear magnetic order consistent with the tetragonal symmetry. Competing ferromagnetic and antiferromagnetic interactions in La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Fe{sub 0.5}O{sub 4}, La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 4} and La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 3.6} induce spin glass properties in these phases. - Graphical abstract: La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Fe{sub 0.5}O{sub 4} and La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 4} have been synthesized by a sol-gel procedure and characterized by diffraction techniques, thermal analysis and Moessbauer spectroscopy. Oxide ion vacancies, created via reduction, are located in the equatorial planes of the K{sub 2}NiF{sub 4}-type structure. La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Fe{sub 0.5}O{sub 3.65} shows antiferromagnetic, noncollinear magnetic order, whereas competing ferromagnetic and antiferromagnetic interactions in La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Fe{sub 0.5}O{sub 4}, La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 4} and La{sub 0.8}Sr{sub 1.2}Co{sub 0.5}Mn{sub 0.5}O{sub 3.6} induce spin glass behaviour.

• OSTI ID: 21370549
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 8 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALINE EARTH METAL COMPOUNDS
ANTIFERROMAGNETISM
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
COBALT COMPOUNDS
COBALT IONS
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
IONS
IRON COMPOUNDS
IRON IONS
LANTHANUM COMPOUNDS
MAGNETISM
MANGANESE COMPOUNDS
MANGANESE IONS
MOESSBAUER EFFECT
NEUTRON DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
POINT DEFECTS
RARE EARTH COMPOUNDS
REDUCTION
SCATTERING
SOL-GEL PROCESS
SPIN GLASS STATE
STRONTIUM COMPOUNDS
SYNTHESIS
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS
VACANCIES
X-RAY DIFFRACTION