title: 61Ni synchrotron radiation-based Mössbauer spectroscopy of nickel-based nanoparticles with hexagonal structure.
abstract: We measured the synchrotron-radiation (SR)-based Mössbauer spectra of Ni-based nanoparticles with a hexagonal structure that were synthesised by chemical reduction. To obtain Mössbauer spectra of the nanoparticles without (61)Ni enrichment, we developed a measurement system for (61)Ni SR-based Mössbauer absorption spectroscopy without X-ray windows between the (61)Ni84V16 standard energy alloy and detector. The counting rate of the (61)Ni nuclear resonant scattering in the system was enhanced by the detection of internal conversion electrons and the close proximity between the energy standard and the detector. The spectrum measured at 4 K revealed the internal magnetic field of the nanoparticles was 3.4 ± 0.9 T, corresponding to a Ni atomic magnetic moment of 0.3 Bohr magneton. This differs from the value of Ni3C and the theoretically predicted value of hexagonal-close-packed (hcp)-Ni and suggested the nanoparticle possessed intermediate carbon content between hcp-Ni and Ni3C of approximately 10 atomic % of Ni. The improved (61)Ni Mössbauer absorption measurement system is also applicable to various Ni materials without (61)Ni enrichment, such as Ni hydride nanoparticles.
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Masuda
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kitao
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kurokuzu
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
authors.forename: Makina
authors.initials: M
authors.lastname: Saito
authors.affiliation: Research and Utilization Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoda
authors.affiliation: Condensed Matter Science Division, Sector of Nuclear Science Research, Japan Atomic Energy Agency, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Takaya
authors.initials: T
authors.lastname: Mitsui
authors.affiliation: Department of Chemistry, Faculty of Science, Kyushu University, 6-10-1, Hakozaki, Fukuoka 812-8581, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hosoi
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitagawa
authors.affiliation: Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.|Condensed Matter Science Division, Sector of Nuclear Science Research, Japan Atomic Energy Agency, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Seto