Hyperfine Interactions

, Volume 156, Issue 1–4, pp 403–410 | Cite as

Characterization and Thermal Behaviour of Garnets from Almandine–Pyrope Series at 1200°C

  • R. Zboril
  • M. Mashlan
  • L. Machala
  • J. Walla
  • K. Barcova
  • P. Martinec
Article

Abstract

The natural garnets from almandine (Fe3Al2Si3O12)–pyrope (Mg3Al2Si3O12) series with the iron to magnesium atomic ratio ranging from 0.2 to 1 were characterised and their thermal behaviour at 1200°C studied by 57Fe Mössbauer spectroscopy, X-ray powder diffraction, X-ray fluorescence, DTA, TG and electron microprobe analysis. The pyrope-type samples with a dominant magnesium content at position 24c in the cubic garnet structure undergo oxidative decomposition at 1200°C resulting in the formation of the paramagnetic spinel Mg(Al,Fe)2O4 structure with a low iron content, enstatite (Mg,Fe)SiO3 and anorthite CaAl2Si2O8 as the host compound for calcium. Contrary to pyropes, the iron-rich garnets exhibit complete oxidation at 1200°C conforming to the formation of magnetically ordered nanocrystalline γ-Fe2O3 or Mg(Fe,Al)2O4 spinels depending on the initial chemical composition of the garnets. In the reaction products of iron-rich garnets, cordierite (Mg2Al4Si5O18) and anorthite were identified as non-ferrous phases.

maghemite nanoparticles thermal decomposition superparamagnetic relaxation 

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References

  1. 1.
    Hlavac, L. and Martinec, P., In: M. Hashish (ed.), Proceedings of 10th American Water Jet Conference, Water Jet Technology Association, St. Louis Houston, 1999, p. 409.Google Scholar
  2. 2.
    Anovitz,L.M., Essene,E.J., Metz,G.W., Bohlen,S.R., Westrum,E.F.and Hemingway,B.S., Geochim. Cosmochim. Acta 57(1993), 4191.ADSCrossRefGoogle Scholar
  3. 3.
    Thiéblot, L., Roux, J. and Richet, P., Eur. J. Mineral. 10(1998), 7.Google Scholar
  4. 4.
    Zboril, R., Mashlan, M., Barcova, K. and Vujtek, M., Hyp. Interact. 139(2002), 597.CrossRefGoogle Scholar
  5. 5.
    Barcova, K., Mashlan, M., Zboril, R., Martinec, P. and Kula, P., Czech. J. Phys. 51(2001), 749.ADSCrossRefGoogle Scholar
  6. 6.
    Zboril, R., Mashlan, M., Barcova, K., Walla, J., Ferrow, E. and Martinec, P., Phys. Chem. Miner. 30(2003), 620.ADSCrossRefGoogle Scholar
  7. 7.
    Murad, E. and Wagner, F. E., Phys. Chem. Miner. 14(1987), 264.CrossRefGoogle Scholar
  8. 8.
    Mitra, S., Applied Mössbauer Spectroscopy, Pergamon Press, Oxford, 1992, p. 137.Google Scholar
  9. 9.
    Amthauer, G., Annersten, H. and Hafner, S. S., Z. Kristallogr. 143(1976), 14.Google Scholar
  10. 10.
    Geiger, C. A., Armbruster, T., Lager, G. A., Jiang, K., Lottermoser, W. and Amthauer, G., Phys. Chem. Miner. 19(1992), 121.CrossRefGoogle Scholar
  11. 11.
    Marshall, I. and Dollase, W., Am. Mineral. 69(1984), 928.Google Scholar
  12. 12.
    Wood, B. J. and Virgo, D., Geochim. Cosmochim. Acta 53(1989), 1277.ADSCrossRefGoogle Scholar
  13. 13.
    Srivastava, K.K.P.,J. Phys. Solid State Phys. C 20(1987), 2161.ADSCrossRefGoogle Scholar
  14. 14.
    Zboril, R., Mashlan, M. and Petridis, D., Chem. Mater. 14(2002), 969.CrossRefGoogle Scholar
  15. 15.
    Šepelák, V., Schultze, D., Krumeich, F., Steinike, U. and Becker, K. D., Solid State Ionics 141–142(2001), 677.CrossRefGoogle Scholar
  16. 16.
    Šepelák, V., Baabe, D., Mienert, D., Schultze, D., Krumeich, F., Litterst, vF. J. and Becker, K. D., J. Magn. Magn. Mater. 257(2003), 377.ADSCrossRefGoogle Scholar

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • R. Zboril
    • 1
  • M. Mashlan
    • 1
  • L. Machala
    • 1
  • J. Walla
    • 1
  • K. Barcova
    • 2
  • P. Martinec
    • 3
  1. 1.Departments of Physical Chemistry and Experimental PhysicsPalacky UniversityOlomoucCzech Republic
  2. 2.Institute of Physics, VSB –Technical University of OstravaCzech Republic
  3. 3.Institute of GeonicsAcademy of SciencesOstravaCzech Republic

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