Dynamics of hydrogen in Pr2Fe17H4 and Pr2Fe17H5 studied by quasielastic neutron scattering
- 1. NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Dr., MS 8562, Gaithersburg, MD 20899-8562 (United States) and Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States)
- 2. NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Dr., MS 8562, Gaithersburg, MD 20899-8562 (United States)
- 3. Institut Universitaire de France, Maison des Universites, 103 Boulevard Saint-Michel, F-75005 Paris, Cedex (France)
- 4. Laboratoire de Cristallographie, CNRS, associe a l'Universite J. Fourier, BP 166X, F-38042 Grenoble, Cedex (France)
Description
Quasielastic neutron scattering (QENS) has been used to investigate the dynamics of hydrogen in Pr2Fe17H4, where isolated hexagons formed by the interstitial tetrahedral (t) sites of the metal lattice host mobile hydrogen atoms (on average, one H atom per hexagon). An activation energy of 0.10 eV has been measured for a localized jump process involving the hopping of these hydrogen atoms among adjacent vertices of each hexagon. This activation energy is somewhat lower compared to that for hydrogen hopping in Pr2Fe17H5, where each hexagon is occupied by two hydrogen atoms. The fraction of the hydrogen atoms immobilized on the t sites by defects in the host metal lattice is slightly higher in Pr2Fe17H4 compared to Pr2Fe17H5. These results are consistent with our earlier view of Pr2Fe17H5 as a system where the hopping of the t-site hydrogen atoms occurs through the correlated jumps of the two H atoms occupying each isolated hexagon
Additional details
Identifiers
- DOI
- 10.1016/j.jallcom.2005.11.064;
- PII
- S0925-8388(05)01813-X;
Publishing Information
- Journal Title
- Journal of Alloys and Compounds
- Journal Volume
- 422
- Journal Issue
- 1-2
- Journal Page Range
- p. 149-152
- ISSN
- 0925-8388
- CODEN
- JALCEU
INIS
- Country of Publication
- Netherlands
- Country of Input or Organization
- International Atomic Energy Agency (IAEA)
- INIS RN
- 38044601
- Subject category
- S36: MATERIALS SCIENCE;
- Descriptors DEI
- ACTIVATION ENERGY; DIFFUSION; HYDROGEN; INELASTIC SCATTERING; IRON HYDRIDES; MILLI EV RANGE; NEUTRON DIFFRACTION; PRASEODYMIUM HYDRIDES; QUASI-ELASTIC SCATTERING
- Descriptors DEC
- COHERENT SCATTERING; DIFFRACTION; DIRECT REACTIONS; ELEMENTS; ENERGY; ENERGY RANGE; HYDRIDES; HYDROGEN COMPOUNDS; IRON COMPOUNDS; NONMETALS; NUCLEAR REACTIONS; PRASEODYMIUM COMPOUNDS; QUASI-FREE REACTIONS; RARE EARTH COMPOUNDS; SCATTERING; TRANSITION ELEMENT COMPOUNDS
Optional Information
- Copyright
- Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.