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Synthesis, structure, and electronic properties LaCa2Mn2O7

Green, M.A., Neumann, D.A. (2000) Synthesis, structure, and electronic properties LaCa2Mn2O7. Chemistry of Materials, 12 (1). pp. 90-97. ISSN 08974756 (ISSN). E-ISSN 1520-5002. (doi:10.1021/cm991094i) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:51147)

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Synthesis of the Ruddlesden-Popper phase, LaCa2Mn2O7 is presented. The difficulty in obtaining a single-phase material, free from a perovskite impurity, is highlighted. Powder X-ray diffraction indicates an orthorhombic symmetry. Powder neutron diffraction reveals a subtle rotation of the MnO6 octahedra and reduction of symmetry to a C-centered orthorhombic cell (Cmcm). Cation ordering occurs with the larger La ions adopting the 12-coordinated site within the perovskite block and the smaller Ca ions situated in the 9-coordinated site in the rock salt layer. Magnetization measurements indicate a weak ferromagnetic transition at around 250 K, which is assigned to a perovskite impurity of 11.4%, as determined by neutron diffraction. Low-temperature neutron diffraction measurements confirms ferromagnetic ordering in the perovskite impurity and show no indication of long-range magnetic ordering in the majority Ruddlesden-Popper phase. Magnetotransport measurements show a metal-insulator transition at around 150 K and magnetoresistance up to 320 K. However, the perovskite impurity limits confidence in the assignment of the origin of the magnetoresistance effect.

Item Type: Article
DOI/Identification number: 10.1021/cm991094i
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Chem. Mater. [Field not mapped to EPrints] AD - Davy Faraday Research Laboratory, Royal Institution of Great Britain, 21 Albemarle Street, London, W1X 4BS, United Kingdom [Field not mapped to EPrints] AD - NIST Centre for Neutron Research, Natl. Inst. of Std. and Technology, Gaithersburg, MD 20899, United States [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: calcium derivative, lanthanum, manganese derivative, article, chemical bond, chemical structure, electronics, magnetism, semiconductor, synthesis, temperature dependence, X ray powder diffraction
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Q Science > QD Chemistry > QD478 Solid State Chemistry
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Giles Tarver
Date Deposited: 21 Oct 2015 13:53 UTC
Last Modified: 16 Nov 2021 10:21 UTC
Resource URI: (The current URI for this page, for reference purposes)

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