Advertisement

Valence State of Europium in EuCuGa, EuAgGa and EuAuGa Compounds

  • S. K. Malik
  • R. Nagarajan
  • D. T. Adroja
  • A. E. Dwight

Abstract

In most of their alloys and intermetallic compounds, the rare earth ions occur in a trivalent valence state. However, some of the rare earth ions are capable of exhibiting more than one valence state. This happens in the case of Ce, Sm, Eu, Tm and Yb. Apart from the normal trivalent state, the cerium ions exhibit a valence state of 4+, and the remaining four rare earth ions exhibit a valence state of 2+. In some cases, the rare earth ion fluctuates between the two valence states. The phenomenon of valence fluctuation [1] reflects in an almost temperature independent susceptibility at low temperatures, a near absence of magnetic ordering (except in a few cases), two sets of lines in the XPS spectra, large value of the electronic specific heat coefficient, and in the case of valence fluctuating Eu ions, moderate to strong temperature dependence of the Mossbauer isomer shift.

Keywords

Valence State Isomer Shift Unit Cell Volume Strong Temperature Dependence Divalent State 
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.
    See, for instance, J.M. Lawrence, P.S. Riseborough and R.D. Parks, Rep. Prog. Phys. 44 (1981) 1.CrossRefGoogle Scholar
  2. 2.
    S.K. Malik, G.K. Shenoy, P.L. Paulose, R. Nagarajan, A.E. Dwight, P.P. Vaishnava and C.W. Kimball, to appear in Hyperfine Interactions.Google Scholar
  3. 3.
    A.E. Dwight, to be published.Google Scholar
  4. 4.
    S.K. Malik, B.D. Dunlap and A.E. Dwight, Presented at the 17th Rare earth Research Conference, Hamilton, Ontario, Canada, June 1986.Google Scholar
  5. 5.
    S.K. Malik, D.T. Adroja, B.D. Padalia and R. Vijayaraghavan, see proceedings of this conference.Google Scholar
  6. 6.
    E.R. Bauminger, G.M. Kalvius and I. Nowik in Mossbauer Isomer Shifts, eds. G.K. Shenoy and F.E. Wagner, North Holland, Amsterdam, 1978, p.661.Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • S. K. Malik
    • 1
    • 2
  • R. Nagarajan
    • 1
  • D. T. Adroja
    • 3
  • A. E. Dwight
    • 2
  1. 1.Tata Institute of Fundamental ResearchBombayIndia
  2. 2.Argonne National LaboratoryArgonneUSA
  3. 3.Department of PhysicsIndian Institute of TechnologyPowai BombayIndia

Personalised recommendations