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INFLUENCE OF HYDROGEN ORDERING ON THE PROTON SPIN-LATTICE RELAXATION TIME IN LANTHANUM SUPERSTOICHIOMETRIC DIHYDRIDES LaH2+c

  • N.Z. NAMORADZE
  • I.G. RATISHVILI
Conference paper
Part of the NATO Security through Science Series A: Chemistry and Biology book series

Abstract

The influence of hydrogen ordering processes on the temperature dependence of the proton spin-lattice relaxation time T1(T) in lanthanum hydrides is estimated. It is shown that on taking into account the dipole-dipole interaction of hydrogen and metal atoms, and the interaction of hydrogen atoms with conduction electrons, an excellent description of the experimental T1(T) dependence can be obtained. It is shown as well that spatial redistribution of ordering octa-hydrogen atoms induces a negligibly small changes in the calculated T1(T) dependence, as the major part of the dipole-dipole interaction is related with the unchanged totalities of tetra-hydrogens and metal atoms.

Keywords

Metal Atom Metal Hydride Occupation Probability Metal Lattice Paramagnetic Impurity 
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References

  1. 1.
    Ratishvili I.G., Vajda P. “Hydrogen ordering in the superstoichiometric rare-earth dihydrides. The case of a system with an energy constanst ratio p = V2 /V1 <1. LaH2+x”. Phys.Rev. B (1996), 53, 581–587.CrossRefADSGoogle Scholar
  2. 2.
    Ratishvili I.G., Vajda P. “Phase diagrams of RH2+x - systems (R = La, Ce, Tb). Results of mean-field calculations”. Journ. All. Comp. (1997), 253–254, 171–174.CrossRefGoogle Scholar
  3. 3.
    Ratishvili I.G., Namoradze N.Z. “Influence of hydrogen ordering on the spinlattice relaxation time in metal hydrides I. The high-temperature limit”. Bull. Georg. Acad. Sciences. (2004), 169 (2), 279–281. “II. The low-temperature limit”. ibid, (2004), 169 (3), 481–483.Google Scholar
  4. 4.
    Phua T.-T. et al. “Paramagnetic impurity effects in NMR determinations of hydrogen diffusion and electronic structure in metal hydrides. Gd3+ in YH2 and LaH2.25”. Phys. Rev. B (1983), 28, 6227–6250.CrossRefADSGoogle Scholar
  5. 5.
    Fukai Y, Kazama S. “NMR studies of anomalous diffusion of hydrogen and phase transition in vanadium-hydrogen alloys”. Acta Metall., (1977), 25, 59–70.CrossRefGoogle Scholar
  6. 6.
    Mamniashvili G.I., Namoradze N.Z., Ratishvili I.G., Sharimanov Yu.G. “Proton Spin-Lattice Relaxation Time in Ordering VHx alloys”. J. Phys. Chem. Solids (2005), 66, 1192–1199.CrossRefADSGoogle Scholar

Copyright information

© Springer 2007

Authors and Affiliations

  • N.Z. NAMORADZE
    • 1
  • I.G. RATISHVILI
    • 2
  1. 1.Institute of CyberneticsGeorgian Academy of SciencesTbilisiGeorgia
  2. 2.E. Andronikashvili Institute of PhysicsGeorgian Academy of SciencesTbilisiGeorgia

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