Structure and magnetic properties of Ca{sub 2}Fe{sub 1-x}Mn{sub x}AlO{sub 5+{delta}}

Journal Article · Mon Sep 15 00:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.06.008· OSTI ID:21128480

Ferreira, L P ^[1]; Waerenborgh, J C; Tsipis, E ^[2]; Lopes, A B ^[3]; Godinho, M ^[4]

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1. CFMC-UL, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal)
2. Dep. Quimica, ITN/CFMC-UL, Estrada Nacional 10, P-2686-953 Sacavem (Portugal)
3. Dep. de Engenharia Ceramica e do Vidro, CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal)
4. CFMC-UL/Dep. Fisica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

Ca{sub 2}Fe{sub 1-x}Mn{sub x}AlO{sub 5} (0{<=}x{<=}1) compounds were prepared by a self-combustion method under air (x=0, 0.1, 0.2 and 0.3) and nitrogen (x=0.5, 0.7 and 1.0). The samples prepared under nitrogen were successfully oxidized after short annealing under air. Both X-ray powder diffraction (XRD) Rietveld analysis and electron diffraction revealed that all compounds adopt the brownmillerite-type structure. All samples present an overall antiferromagnetic behaviour and data from magnetic measurements and Moessbauer spectroscopy allowed to conclude that the transition temperature decreases as Mn content increases for x{<=}0.3 and increases in the case of the x{>=}0.5 compounds. Except for x=1, chemical disorder due to the occupancy of both octahedral and tetrahedral sites by different metals as well as the competition between different moments' orientation induce a complex magnetic behaviour characterized by magnetic frustration and canted antiferromagnetism. Moessbauer spectroscopy and chemical titrations also allowed to conclude about the preferential oxidation of Mn{sup 3+} over Fe{sup 3+}, obtained by thermal treatment under air of the x=0.5 and 0.7 compositions. - Graphical abstract: Structure of the Ca{sub 2}Fe{sub 1-x}Mn{sub x}AlO{sub 5} compound and electron diffraction pattern obtained along the [1-bar 01] zone axis (x=0.2), showing a brownmillerite structure.

• OSTI ID: 21128480
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 9; Other Information: DOI: 10.1016/j.jssc.2008.06.008; PII: S0022-4596(08)00308-3; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM COMPOUNDS
ANNEALING
ANTIFERROMAGNETISM
CALCIUM COMPOUNDS
COMBUSTION
ELECTRON DIFFRACTION
IRON COMPOUNDS
IRON IONS
MAGNETIC PROPERTIES
MANGANESE COMPOUNDS
MANGANESE IONS
MOESSBAUER EFFECT
OXIDES
TITRATION
TRANSITION TEMPERATURE
X-RAY DIFFRACTION