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Please use this identifier to cite or link to this item: http://apo.ansto.gov.au/dspace/handle/10238/1453

Title: Crystal and magnetic structures of LaCa2Fe3O8 and NdCa2Fe3O8.
Authors: Hudspeth, JM
Goossens, DJ
Studer, AJ
Withers, RL
Noren, L
Keywords: Neutron Diffraction
Crystal Structure
Magnetic Moments
X-Ray Diffraction
Electron Diffraction
Oxygen
Issue Date: 25-Mar-2009
Publisher: Institute of Physics
Citation: Hudspeth, J. M., Goossens, D. J., Studer, A. J., Withers, R. L., & Noren, L. (2009). Crystal and magnetic structures of LaCa2Fe3O8 and NdCa2Fe3O8. Journal of Physics-Condensed Matter, 21(12), 8.
Abstract: The crystal and magnetic structures of LaCa2Fe3O8 and NdCa2Fe3O8 have been established using a combination of x-ray, neutron and electron diffraction. It was already considered likely that LaCa2Fe3O8 and NdCa2Fe3O8 were made up of stacked perovskite-like layers of FeO6 octahedra, with every third layer being replaced by a layer of tetrahedrally coordinated Fe, rather like a variation on the Brownmillerite (Ca2Fe2O5) structure type. We have gone further and determined a likely space group for this Grenier phase and determined the magnetic structure of the compounds at room temperature. The space group is found to be P2(1)ma (b axis as the long axis), and the crystal structure has been refined, subject to the stacking faulting along the long axis that is apparent in electron diffraction patterns. The magnetic structure of LaCa2Fe3O8 is shown to consist of antiferromagnetically ordered Fe3+ ions on a collinear G-type antiferromagnetic structure, with the magnetic moments most likely (anti) parallel with the c axis, and of magnitude 3.4 +/- 0.2 mu(B) (3.6 +/- 0.2 mu(B) for NdCa2Fe3O8). The result is reasonable given the magnetic structures of the end members of the La1-xCaxFeO3 series, LaFeO3 (x = 0) and Ca2Fe2O5 (x = 1). © 2009, Institute of Physics
URI: http://dx.doi.org/10.1088/0953-8984/21/12/124206
http://apo.ansto.gov.au/dspace/handle/10238/1453
ISSN: 0953-8984
Appears in Collections:Journal Articles

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