Hydrogen Dynamics in the Hexagonal Ho2Fe17H4 and Y2Fe17H4.2: Inelastic and Quasielastic Neutron Scattering Studies

Published

May 28, 2017

Author(s)

A. V. Skripov, O. Isnard, N. V. Mushnikov, P. B. Terent'ev, V. S. Gaviko, Terrence J. Udovic

Abstract

The vibrational spectra of hydrogen and the parameters of H jump motion in the hexagonal Th₂Ni₁₇-type compounds Ho₂Fe₁₇H₄ and Y₂Fe₁₇G_4,2 have been studied by means of inelastic and quasielastic neutron scattering. It is found that hydrogen atoms occupying interstitial Ho(Y)₂Fe₂ sites in both compounds participate in the fast localized jump motion over the hexagons formed by these tetrahedral sites. The temperature dependence of the H jump rate is well described by the Arrhenius law over wide T ranges (100 - 340 K for Ho₂Fe₁₇H₄ and 140-360 K for Y₂Fe₁₇H_4.2) with the activation energies of 54(4) meV and 84(7) meV, respectively. For Ho₂Fe₁₇H₄, the localized hydrogen jump motion is found to be the fastest among all R₂Fe₁₇ hydrides studies so far. At room temperature, the H jump rate in Ho₂Fe₁₇H₄ derived from our quasielastic neutron scattering data reaches 6.4 x 10¹¹S^-1.

Citation

Journal of Alloys and Compounds

Volume

720

Pub Type

Journals

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Keywords

Ho2Fe17H4, hydrogen, hydrogen trapping, hydrogen mobility, inelastic neutron scattering, jump diffusion, neutron scattering, quasielastic neutron scattering, Y2Fe17H4

Citation

Skripov, A. , Isnard, O. , Mushnikov, N. , Terent'ev, P. , Gaviko, V. and Udovic, T. (2017), Hydrogen Dynamics in the Hexagonal Ho₂Fe₁₇H₄ and Y₂Fe₁₇H_4.2: Inelastic and Quasielastic Neutron Scattering Studies, Journal of Alloys and Compounds, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923020 (Accessed September 13, 2024)