Structural and Magnetic Properties of Nd₁₈Li₈Co₄₋ₓFeₓO39-y and Nd₁₈Li₈Co₄₋ₓTiₓO39-y

Abstract

Nd18Li8Co3FeO39-y, Nd 18Li8CoFe3O39-y and Nd 18Li8Co3TiO39-y have been synthesised and characterised by neutron powder diffraction, magnetometry and Mössbauer spectroscopy. Their cubic structure (Pm3n, a~11.9 Å) 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 NdO framework. Each compound has an incomplete oxide sublattice (y~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 Nd18Li 8CoFe3O39-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.

Department(s)

Chemistry

Keywords and Phrases

Antiferro-magnetic Interactions; Coordination Sites; Cubic Structure; High Concentration; Mixed-metal Oxides; Octahedral Sites; Ssbauer Spectroscopies; Structural And Magnetic Properties; Sub-lattices; TiO; Antiferromagnetic Materials; Antiferromagnetism; Diffraction; Ferromagnetism; Glass; Iron Oxides; Magnetic Properties; Molybdenum; Neodymium; Spin Glass; Transition Metals; Lithium; Antiferromagnetism; Mixed-metal Oxides; Neutron Diffraction; Spin Glass

International Standard Serial Number (ISSN)

0022-4596

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Elsevier, All rights reserved.

Publication Date

01 Sep 2011

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