Structural and magnetic properties of Nd{sub 18}Li{sub 8}Co{sub 4-x}Fe{sub x}O{sub 39-y} and Nd{sub 18}Li{sub 8}Co{sub 4-x}Ti{sub x}O{sub 39-y}

Journal Article · Thu Sep 15 04:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.07.020· OSTI ID:21580244

Dutton, Sian E ^[1]; Grandjean, Fernande ^[2]; Long, Gary J ^[3]; Thammajak, Nirawat; Wisetsuwannaphum, Sirikarn ^[1]

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1. Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR (United Kingdom)
2. Faculty of Sciences, University of Liege, B-4000 Sart-Tilman (Belgium)
3. Department of Chemistry, Missouri University of Science and Technology, University of Missouri, Rolla, Missouri 65409-0010 (United States)

Nd{sub 18}Li{sub 8}Co{sub 3}FeO{sub 39-y}, Nd{sub 18}Li{sub 8}CoFe{sub 3}O{sub 39-y} and Nd{sub 18}Li{sub 8}Co{sub 3}TiO{sub 39-y} have been synthesised and characterised by neutron powder diffraction, magnetometry and Moessbauer spectroscopy. Their cubic structure (Pm3-bar n, a{approx}11.9 A) is based on intersecting <1 1 1> chains comprised of alternating octahedral and trigonal-prismatic coordination sites. These chains lie within hexagonal-prismatic cavities formed by a Nd-O framework. Each compound has an incomplete oxide sublattice (y{approx}1), with vacancies located around the octahedral sites that lie at the points of chain intersection. These sites are fully occupied by a disordered arrangement of transition-metal cations but only 75% of the remaining octahedral sites are occupied. The trigonal-prismatic sites are fully occupied by lithium except in the case of Nd{sub 18}Li{sub 8}CoFe{sub 3}O{sub 39-y} where some iron is present. Antiferromagnetic interactions are present on the Nd sublattice in each composition, but a spin glass forms below 5 K when a high concentration of spins is also present on the octahedral sites. - Graphical Abstract: Cation and anion vacancies are found to coexist in mixed-metal oxides that adopt the La{sub 18}Li{sub 8}Rh{sub 5}O{sub 39} structure. Highlights: > Coexistence of anion and cation vacancies in compounds adopting the La{sub 18}Li{sub 8}Rh{sub 5}O{sub 39} structure. > Variation of the degree of magnetic frustration with the chemical composition in the La{sub 18}Li{sub 8}Rh{sub 5}O{sub 39} structure. > Controlling influence of the magnetic properties of the lanthanide cation becomes clear.

• OSTI ID: 21580244
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 9 Vol. 184; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ANTIFERROMAGNETISM
CATIONS
CHAINS
CHARGED PARTICLES
CHEMICAL COMPOSITION
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
ELEMENTS
IONS
MAGNETIC PROPERTIES
MAGNETISM
METALS
MOESSBAUER EFFECT
NEUTRON DIFFRACTION
PHYSICAL PROPERTIES
RARE EARTHS
SCATTERING
SPIN GLASS STATE