Magnetic properties of KNaMSi{sub 4}O{sub 10} compounds (M=Mn,Fe,Cu)
- CICECO and Chemistry Department, Universidade de Aveiro, 3810-193 Aveiro (Portugal)
- NSSD-MSTD, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6475 (United States)
In the present work the synthesis and magnetic properties of three compounds with formula KNaMSi{sub 4}O{sub 10}(M=Mn,Fe,Cu) are described. These compounds are synthetic analogs to natural occurring minerals: fenaksite-Fe{sup 2+}, litidionite-Cu{sup 2+} and manaksite-Mn{sup 2+}. The crystal structure consists of complex silicate chains interconnected by edge-sharing MO{sub 5} square pyramids dimerized in M{sub 2}O{sub 8} units. This charged metal-silicate framework is compensated by monovalent alkali metals (K{sup +}, Na{sup +}). Despite the isostructural nature of these compounds, and the consequent similarity of the M-O topology, that rules the magnetic properties, these are quite different. While there are antiferromagnetic (AF) interactions within the Mn and Cu dimers (exchange interaction J=-3.83(1) and -2.86(3)K, respectively) with no long range order, a ferromagnetic interaction within Fe dimers (J=+7.6(1)K) is observed with a three-dimensional transition at 9 K to an AF ground state. The magnetic behavior is analyzed using the HDVV (Heisenberg-Dirac-Van Vleck) formalism and discussed in the light of the crystal structure. - Magnetic susceptibility times temperature. The antiferromagnetic arrangement within Mn and Cu dimers is evident (due to the positive derivative at lower temperatures). For the Fe-counterpart a three-dimensional transition to an antiferromagnetic (AF) inter-dimer interaction is found upon cooling. Above this transition the drop in {chi}T is a signature of ferromagnetic intra-dimer interactions.
- OSTI ID:
- 21212186
- Journal Information:
- Journal of Solid State Chemistry, Vol. 182, Issue 2; Other Information: DOI: 10.1016/j.jssc.2008.10.024; PII: S0022-4596(08)00516-1; 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
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIFERROMAGNETISM
COPPER COMPOUNDS
COPPER IONS
CRYSTAL STRUCTURE
EXCHANGE INTERACTIONS
HYDROTHERMAL SYNTHESIS
IRON COMPOUNDS
IRON IONS
MAGNETIC SUSCEPTIBILITY
MANGANESE COMPOUNDS
MANGANESE IONS
POTASSIUM COMPOUNDS
SILICATES
SODIUM COMPOUNDS
SODIUM IONS