Hydrogen Dynamics in Laves-Phase Hydride YFe2H2.6: Inelastic and Quasielastic Neutron Scattering Studies

Published

May 15, 2014

Author(s)

A. V. Skripov, V. Paul-Bancour, Terrence J. Udovic, John J. Rush

Abstract

The vibrational spectrum of hydrogen and the parameters of H jump motion in the C15-type compound YFe₂H_2.6 have been studied by means of inelastic and quasielastic neutron scattering. It is found that hydrogen atoms occupying tetrahedral interstitial g (Y₂Fe₂) sites participate in the fast localized jump motion. The behavior of the elastic incoherent structure factor as a function of momentum transfer (measured up to Q_max ≅4 Å^-1) is consistent with the two-site motion of H atoms within pairs of closely spaced g sites. In the studied T range of 140 K to 390 K, the temperature dependence of the jump rate of this localized motion is found to be non-Arrhenius; however, it can be described by two Arrhenius-like terms with the activation energies of 42 meV and 10 meV in the ranges 295 K to 390 K and 140 K to 240 K, respectively. Our results also indicate that hydrogen dynamics in YFe₂H_2.6 is affected by considerable local lattice distortions resulting from hydrogenation of YFe₂.

Citation

Journal of Alloys and Compounds

Volume

595

Pub Type

Journals

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Keywords

dynamics, hydrogen, Laves phase, localized motion, metal hydride, neutron scattering, neutron vibrational spectroscopy, quasielastic neutron scattering, ZrFe2

Citation

Skripov, A. , Paul-Bancour, V. , Udovic, T. and Rush, J. (2014), Hydrogen Dynamics in Laves-Phase Hydride YFe₂H_2.6: Inelastic and Quasielastic Neutron Scattering Studies, Journal of Alloys and Compounds, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914614 (Accessed April 20, 2024)