TY - JOUR
T1 - Variation of hydrogen occupation in LaNi4.78Sn0.22Dx along the P-C isotherms studied by in situ neutron powder diffraction
AU - Nakamura, Yumiko
AU - Bowman, Robert C.
AU - Akiba, Etsuo
N1 - Funding Information:
The authors thank Dr. F. Izumi for providing and modifying the Rietveld refinement software, RIETAN-TN. The authors thank Prof. K. Kamiyama of the High-Energy Accelerator Research Organization, Dr. T. Ishigaki of Japan Atomic Research Institute and Mr. K. Iwase of the Graduate University of Advanced Studies for technical assistance in neutron diffraction measurements. A part of this research was financially supported by the Ministry of Economy Trade and Industry (METI) of Japan. This research was partially performed at the Jet Propulsion Laboratory, which is operated by the California Institute of Technology under contract with the U.S. National Aeronautics and Space Administration (NASA).
PY - 2007/4/4
Y1 - 2007/4/4
N2 - We performed in situ neutron powder diffraction measurements of LaNi4.78Sn0.22Dx along the absorption and desorption pressure-composition (P-C) isotherms using 90° banks of a TOF diffractometer. Structure of the hydride phase for various hydrogen contents was analyzed by the Rietveld method. Variation of the hydrogen occupation and the lattice parameters for the hydride phase was investigated. The full hydride LaNi4.78Sn0.22D6.1 has a P6mm structure with four hydrogen sites; 3c sites (O[La2Ni4]), 6e1 sites (T[La2Ni2]), 6e2 sites (T[La1Ni3]) and 2b sites (T[Ni4]) with occupancies of 0.98(2), 0.34(1), 0.168(9) and 0.24(2), respectively. The 3c site was fully occupied regardless of the total hydrogen content. Occupancies of the other three sites changed depending on the hydrogen content, with hysteresis between absorption and desorption in the two-phase region. The hydrogen occupation and the lattice parameters for the hydride phase varied even in the two-phase region during desorption.
AB - We performed in situ neutron powder diffraction measurements of LaNi4.78Sn0.22Dx along the absorption and desorption pressure-composition (P-C) isotherms using 90° banks of a TOF diffractometer. Structure of the hydride phase for various hydrogen contents was analyzed by the Rietveld method. Variation of the hydrogen occupation and the lattice parameters for the hydride phase was investigated. The full hydride LaNi4.78Sn0.22D6.1 has a P6mm structure with four hydrogen sites; 3c sites (O[La2Ni4]), 6e1 sites (T[La2Ni2]), 6e2 sites (T[La1Ni3]) and 2b sites (T[Ni4]) with occupancies of 0.98(2), 0.34(1), 0.168(9) and 0.24(2), respectively. The 3c site was fully occupied regardless of the total hydrogen content. Occupancies of the other three sites changed depending on the hydrogen content, with hysteresis between absorption and desorption in the two-phase region. The hydrogen occupation and the lattice parameters for the hydride phase varied even in the two-phase region during desorption.
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U2 - 10.1016/j.jallcom.2006.05.082
DO - 10.1016/j.jallcom.2006.05.082
M3 - Article
AN - SCOPUS:33847254401
SN - 0925-8388
VL - 431
SP - 148
EP - 154
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1-2
ER -