Title

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

Abstract

Nd₁₈Li₈Co3FeO39-y, Nd₁₈Li₈CoFe3O39-y and Nd₁₈Li₈Co3TiO39-y have been synthesised and characterised by neutron powder diffraction, magnetometry and Mössbauer spectroscopy. Their cubic structure (Pm3-n, 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 Nd-O 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 Nd₁₈Li₈CoFe3O39-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

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Elsevier, All rights reserved.


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