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Title: Structural and magnetic characterization of BiFe{sub x}Mn{sub 2-x}O{sub 5} oxides (x=0.5, 1.0)

The title compounds have been synthesized by a citrate technique followed by thermal treatments in air (BiFe{sub 0.5}Mn{sub 1.5}O{sub 5}) or under high oxygen pressure conditions (BiFeMnO{sub 5}), and characterized by X-ray diffraction (XRD), neutron powder diffraction (NPD) and magnetization measurements. The crystal structures have been refined from NPD data in the space group Pbam at 295 K. These phases are isostructural with RMn{sub 2}O{sub 5} oxides (R=rare earths) and contain infinite chains of Mn{sup 4+}O{sub 6} octahedra sharing edges, linked together by (Fe,Mn){sup 3+}O{sub 5} pyramids and BiO{sub 8} units. These units are strongly distorted with respect to those observed in other RFeMnO{sub 5} compounds, due to the presence of the electronic lone pair on Bi{sup 3+}. It is noteworthy the certain level of antisite disorder exhibited in both samples, where the octahedral positions are partially occupied by Fe cations, and vice versa. BiFe{sub x}Mn{sub 2-x}O{sub 5} (x=0.5, 1.0) are short-range magnetically ordered below 20 K for x=0.5 and at 40 K for x=1.0. The main magnetic interactions seem to be antiferromagnetic (AFM); however, the presence of a small hysteresis in the magnetization cycles indicates the presence of some weak ferromagnetic (FM) interactions. - Graphical Abstract: BiFe{sub x}Mn{sub 2-x}O{submore » 5} (x=0.5, 1.0) samples are isostructural with BiMn{sub 2}O{sub 5}, belonging to the Pbam space group. The crystal structure contains infinite chains of edge-sharing Mn{sup 4+}O{sub 6} octahedra, interconnected by dimer units of Fe{sup 3+}O{sub 5} square pyramids. These units are strongly distorted due to the presence of the electronic lone pair on Bi{sup 3+}. They are magnetically ordered at low temperatures. The main magnetic interactions seem to be antiferromagnetic with the presence of some weak ferromagnetic response. Highlights: > Two new compounds of formula BiFe{sub x}Mn{sub 2-x}O{sub 5} (x=0.5, 1.0) have been obtained. > Their crystallographic structure is isotypical with that of RMn{sub 2}O{sub 5} materials. > The presence of the electronic lone pair on Bi{sup 3+} severely distorts the crystal structure. > There is no establishment of a long-range ferrimagnetic structure.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Instituto de Ciencia de Materiales de Madrid, C.S.I.C., Cantoblanco, E-28049 Madrid (Spain)
  2. (United States)
  3. Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Boulevard, Sofia 1784 (Bulgaria)
  4. Institut Laue-Langevin, BP156X, Grenoble F-38042 (France)
Publication Date:
OSTI Identifier:
21580267
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 184; Journal Issue: 9; Other Information: DOI: 10.1016/j.jssc.2011.07.009; PII: S0022-4596(11)00378-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIFERROMAGNETISM; BISMUTH IONS; CRYSTAL STRUCTURE; CRYSTALLOGRAPHY; ELECTRICAL PROPERTIES; HEAT TREATMENTS; INTERACTIONS; IRON IONS; MAGNETIC PROPERTIES; MAGNETIZATION; MANGANESE IONS; NEUTRON DIFFRACTION; OXIDES; RARE EARTHS; SPACE GROUPS; TEMPERATURE RANGE 0065-0273 K; X-RAY DIFFRACTION CHALCOGENIDES; CHARGED PARTICLES; COHERENT SCATTERING; DIFFRACTION; ELEMENTS; IONS; MAGNETISM; METALS; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; SCATTERING; SYMMETRY GROUPS; TEMPERATURE RANGE