@article{fac0cb4704644f31bbdbbfd7c62e7ac5,
title = "Hydrogen diffusion in bulk and nanocrystalline palladium: A quasielastic neutron scattering study",
abstract = "The diffusion dynamics of hydrogen in bulk and nanocrystalline palladium has been examined using quasielastic neutron scattering (QENS). With respect to bulk PdH0.73, two relaxation processes were found. For both processes, the variation of the relaxation times with momentum transfer was well reproduced by a model of jump diffusion between adjacent octahedral sites. Upon cooling the fast relaxation fraction decreases. The result suggests that the slow relaxation corresponds to jumps between the ground states and the fast one between excited states. In nanocrystalline PdH0.47 with a size of 8 nm, we found a fast diffusion process with a smaller activation energy in addition to the one observed in the bulk sample. This process could be due to the motion of hydrogen atoms in the subsurface region where the potential energy surface is substantially modified by surface strain/distortion effects.",
author = "Maiko Kofu and Naoki Hashimoto and Hiroshi Akiba and Hirokazu Kobayashi and Hiroshi Kitagawa and Madhusudan Tyagi and Antonio Faraone and Copley, {John R.D.} and Wiebke Lohstroh and Osamu Yamamuro",
note = "Funding Information: We are grateful to M. Nagao for technical support during the experiments on NSE at the NCNR. This work was supported by Core Research for Evolutional Science and Technology (CREST) from Japan Science and Technology Agency (JST). The experiments at NCNR were financially supported by General User Program for Neutron Scattering Experiments, Institute for Solid State Physics, The University of Tokyo. This work utilized facilities supported in part by the National Science Foundation under Agreement No. DMR-1508249. Certain commercial equipment, instruments, or materials are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. Publisher Copyright: {\textcopyright} 2016 American Physical Society.",
year = "2016",
month = aug,
day = "29",
doi = "10.1103/PhysRevB.94.064303",
language = "English",
volume = "94",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Physical Society",
number = "6",
}