Advertisement

Hyperfine Interactions

, Volume 67, Issue 1–4, pp 443–446 | Cite as

Mössbauer study of Brazilian columbite

  • R. Garg
  • O. D. Rodrigues
  • E. Galvão Da Silva
  • V. K. Garg
Mineralogy, Geology and Archeology

Abstract

Columbite mineral from Lavra de Golconda in Governador Valadares, Minas Gerais, Brazil has been characterized by X-ray diffraction and electron microscopy. It has short prismatic nonconducting crystals with noninherent impurities of quartz, and exhibits one set of perfect cleavage. The reflectance is lowest normal to the cleavage surface, almost black. The surface is uneven and has small particles in a regular manner. On the other cleavage surface there is a regular pattern of white adherent impurity. The chemical composition of (Fe0.32Mn0.68)Nb2O6 was determined by mass spectrometry. The mineral has been studied by Mössbauer spectroscopy down to liquid nitrogen temperature. The isomer shift is 1.15 mm/sec and is almost temperature independent, but, the quadrupole splitting (1.55 mm/s at room temperature) is strongly temperature dependent (2.23 mm/s at liquid nitrogen temperature with large linewidth). This temperature dependence is explained in terms of relatively small crystal-field splitting of the t2g levels.

Keywords

Microscopy Electron Microscopy Thin Film Quartz Mass Spectrometry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    Dana's System of Mineralogy, Vol. 1 (John Wiley & Sons, 1951) p. 780; R.V. Dietrich, in:Mineral Tables (McGraw Hill Book Company, New York, 1969).Google Scholar
  2. [2]
    R.W.G. Wyckoff, in:Crystal Structures, Vol. II (Interscience Publishers, Inc., New York, 1951).Google Scholar
  3. [3]
    International Tables for X-ray Crystallography, Vol. 1 (Kynoch Press, Birmingham, England, 1952).Google Scholar
  4. [4]
    J. Oliveira, C. Alves, Jr., C.A. Barros, R.A. Pereira and C.A. Santos, in:Proc. First Latin American Conference On The Applications of Mössbauer Effect Rio de Janeiro, 1988 (World Scientific Co, Singapore, 1990) p. 385.Google Scholar
  5. [5]
    N.E. Erickson, in: Advances In Chemistry Series No. 68.The Mössbauer Effect and Its Application In Chemistry (The American Chemical Society 1967, USA) p. 87.Google Scholar
  6. [6]
    D. Palumbo, Nuovo Cimento 8 (1958) 271.Google Scholar
  7. [7]
    C.J. Ballhausen, in:Ligand Field Theory (McGraw Hill Book Company, New York, 1962).Google Scholar
  8. [8]
    G.M. Bancroft, in:Mössbauer Spectroscopy—An Introduction For Inorganic Chemists and Geochemists (Halsted Press, New York, 1973).Google Scholar
  9. [9]
    M. Eibschutz, U. Ganiel and S. Shtrikman, Phys. Rev. 156 (1967) 259.CrossRefADSGoogle Scholar
  10. [10]
    R. Ingalls, Phys. Rev. 133 (1964) A787.CrossRefADSGoogle Scholar

Copyright information

© J.C. Baltzer A.G. Scientific Publishing Company 1991

Authors and Affiliations

  • R. Garg
    • 1
  • O. D. Rodrigues
    • 1
  • E. Galvão Da Silva
    • 2
  • V. K. Garg
    • 1
  1. 1.Departamento de Física e QuímicaUniversidade Federal do Espirito SantoVitóriaBrazil
  2. 2.Departamento de FísicaUniversidade Federal de Minas GeraisBelo HorizonteBrazil

Personalised recommendations