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Journal Articles

Measurement of neutron scattering cross section of nano-diamond with particle diameter of approximately 5 nm in energy range of 0.2 meV to 100 meV

Teshigawara, Makoto; Tsuchikawa, Yusuke*; Ichikawa, Go*; Takata, Shinichi; Mishima, Kenji*; Harada, Masahide; Oi, Motoki; Kawamura, Yukihiko*; Kai, Tetsuya; Kawamura, Seiko; et al.

Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06

 Times Cited Count:7 Percentile:75.46(Instruments & Instrumentation)

A nano-diamond is an attractive neutron reflection material below cold neutron energy. The total neutron cross section of a nano-diamond was derived from a neutron transmission measurement over the neutron energy range of 0.2 meV to 100 meV because total neutron cross section data were not available. The total cross section of a nano-diamond with particle size of approximately 5 nm increased with a decrease in neutron energy to 0.2 meV. It was approximately two orders of magnitude larger than that of graphite at 0.2 meV. The contribution of inelastic scattering to the total cross section was to be shown negligible small at neutron energies of 1.2, 1.5, 1.9, 2.6, and 5.9 meV in the inelastic neutron scattering measurement. Moreover, small-angle neutron scattering measurements of the nano-diamond showed a large scattering cross section in the forward direction for low neutron energies.

Journal Articles

Localized 5$$f^2$$ states in UPd$$_5$$Al$$_2$$ and valence crossover in the Vicinity of Heavy-Fermion superconductivity

Metoki, Naoto; Haga, Yoshinori; Yamamoto, Etsuji; Matsuda, Masaaki*

Journal of the Physical Society of Japan, 87(11), p.114712_1 - 114712_9, 2018/11

 Times Cited Count:2 Percentile:29.78(Physics, Multidisciplinary)

The localized 5$$f$$ states with 5$$f^2$$ ($$^3H_4$$) configuration of U$$^{4+}$$ ion have been revealed in UPd$$_5$$Al$$_2$$. We found that the low-lying states are the same as PrPd$$_5$$Al$$_2$$ flat orbitals with large $$J_z$$ are stabilized by a two-dimensional CEF potential in the unique crystal structure. The present study involves the valence crossover from tetravalent to trivalent in a series of AnPd$$_5$$Al$$_2$$, demonstrated by lattice and/or transport anomaly as well as many body effects in the vicinity of the boundary. The valence instability plays important role for the unusual heavy fermion superconductivity in NpPd$$_5$$Al$$_2$$.

Journal Articles

$$f$$-electron states in PrPd$$_5$$Al$$_2$$

Metoki, Naoto; Yamauchi, Hiroki; Suzuki, Hiroyuki*; Kitazawa, Hideaki*; Hagiwara, Masato*; Masuda, Takatsugu*; Aczel, A. A.*; Chi, S.*; Hong, T.*; Matsuda, Masaaki*; et al.

Journal of the Physical Society of Japan, 87(9), p.094704_1 - 094704_8, 2018/09

 Times Cited Count:5 Percentile:54.08(Physics, Multidisciplinary)

The $$f$$-electron states of PrPd$$_5$$Al$$_2$$ were revealed by neutron inelastic scattering. The flat $$f$$-orbitals with large $$J_z$$ become stable under the two-dimensional CEF potential of unique crystal structure, which is the origin of the Ising anisotropy. A systematic understanding is possible in RPd$$_5$$Al$$_2$$ based on this CEF potential. Especially the $$XY$$-type anisotropy in NpPd$$_5$$Al$$_2$$ can be qualitatively understood with the positive Stevens factors. It mean that the local property is important for the physical properties of RPd$$_5$$Al$$_2$$ including the heavy fermion superconductivity in NpPd$$_5$$Al$$_2$$.

Journal Articles

Neutron inelastic scattering study of the $$f$$-electron states in NdPd$$_5$$Al$$_2$$

Metoki, Naoto; Yamauchi, Hiroki; Suzuki, Hiroyuki*; Kitazawa, Hideaki*; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro

Journal of the Physical Society of Japan, 87(8), p.084708_1 - 084708_7, 2018/08

 Times Cited Count:5 Percentile:54.08(Physics, Multidisciplinary)

Inelastic neutron scattering experiments were carried out in order to study the $$f$$-electron states of NdPd$$_5$$Al$$_2$$The CEF levels at 0K, 35.4K, 88.3K, 101.5K, and 198.8K were clarified from the excitation spectra. The $$Gamma_6$$ ground state contains the orbital with $$J_z=pm9/2$$ as a main component due to a large negative B$$_{20}=-1.4$$K, which is the origin of the strong uniaxial anisotropy. The estimated magnetic moment, the calculated susceptibility, magnetization curve, and specific heat are in good agreement with the experimental data. The existence of a common charge distribution with CePd$$_5$$Al$$_2$$ and PrPd$$_5$$Al$$_2$$. Indicates that a localized character is important even in actinide-based iso-structural compounds as actually observed in UPd$$_5$$Al$$_2$$ and also NpPd$$_5$$Al$$_2$$, in which the valence crossover plays important role for the heavy fermion superconductivity.

Journal Articles

Experimental investigation of the glass transition of polystyrene thin films in a broad frequency range

Inoue, Rintaro*; Kanaya, Toshiji*; Yamada, Takeshi*; Shibata, Kaoru; Fukao, Koji*

Physical Review E, 97(1), p.012501_1 - 012501_6, 2018/01

 Times Cited Count:8 Percentile:75.32(Physics, Fluids & Plasmas)

In this study, we investigate the $$alpha$$ process of a polystyrene thin film using inelastic neutron scattering (INS), dielectric relaxation spectroscopy (DRS), and thermal expansion spectroscopy (TES). The DRS and TES measurements exhibited a decrease in glass transition temperature ($$T_{rm g}$$) with film thickness. On the other hand, an increase in $$T_{rm g}$$ was observed in INS studies. In order to interpret this contradiction, we investigated the temperature dependence of the peak frequency ($$f_{rm m}$$) of the $$alpha$$ process probed by DRS and TES. The experiments revealed an increase in the peak frequency ($$f_{rm m}$$) with decreasing film thickness in the frequency region. This observation is consistent with the observed decrease in $$T_{rm g}$$ with thickness. The discrepancy between INS and DRS or TES descriptions of the $$alpha$$ process is likely to be attributed to a decrease in the apparent activation energy with film thickness and reduced mobility, due to the impenetrable wall effect.

Journal Articles

Polar rotor scattering as atomic-level origin of low mobility and thermal conductivity of perovskite CH$$_{3}$$NH$$_{3}$$PbI$$_{3}$$

Li, B.; Kawakita, Yukinobu; Liu, Y.*; Wang, M.*; Matsuura, Masato*; Shibata, Kaoru; Kawamura, Seiko; Yamada, Takeshi*; Lin, S.*; Nakajima, Kenji; et al.

Nature Communications (Internet), 8, p.16086_1 - 16086_9, 2017/06

 Times Cited Count:52 Percentile:91.93(Multidisciplinary Sciences)

Journal Articles

Impurity effects in the microscopic elastic properties of polycrystalline Mg-Zn-Y alloys with a synchronised long-period stacking ordered phase

Hosokawa, Shinya*; Kimura, Koji*; Yamasaki, Michiaki*; Kawamura, Yoshihito*; Yoshida, Koji*; Inui, Masanori*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Kawakita, Yukinobu; Ito, Shinichi*

Journal of Alloys and Compounds, 695, p.426 - 432, 2017/02

 Times Cited Count:3 Percentile:24.7(Chemistry, Physical)

Journal Articles

Inelastic neutron scattering study on low-energy excitations of the heavy-fermion superconductor PrOs$$_4$$Sb$$_{12}$$

Kuwahara, Keitaro*; Iwasa, Kazuaki*; Kogi, Masafumi*; Kaneko, Koji; Metoki, Naoto; Raymond, S.*; M$'e$asson, M.-A.*; Flouquet, J.*; Sugawara, Hitoshi*; Aoki, Yuji*; et al.

Physica B; Condensed Matter, 385-386(Part 1), p.82 - 84, 2006/11

 Times Cited Count:3 Percentile:18.82(Physics, Condensed Matter)

We report inelastic neutron scattering experiments performed to investigate the low energy magnetic excitations on single crystals of the heavy-fermion superconductor PrOs$$_4$$Sb$$_{12}$$. The observed excitation clearly softens at a wave vector Q=(1,0,0), which is the same as the modulation vector of the field-induced antiferro-quadrupolar ordering, and its intensity at Q=(1,0,0) is smaller than that around the zone center. This result directly evidences that this excitonic behavior is derived mainly from nonmagnetic quadrupolar interactions. Furthermore, the narrowing of the linewidths of the excitations below the superconducting transition temperature indicates the close connection between the superconductivity and the excitons.

Journal Articles

Direct observation of quadrupolar excitons in the heavy-fermion superconductor PrOs$$_4$$Sb$$_12$$

Kuwahara, Keitaro*; Iwasa, Kazuaki*; Kogi, Masafumi*; Kaneko, Koji; Metoki, Naoto; Raymond, S.*; M$'e$asson, M.-A.*; Flouquet, J.*; Sugawara, Hitoshi*; Aoki, Yuji*; et al.

Physical Review Letters, 95(10), p.107003_1 - 107003_4, 2005/09

 Times Cited Count:91 Percentile:92.46(Physics, Multidisciplinary)

We report inelastic neutron scattering experiments performed to investigate the low energy magnetic excitations on single crystals of the heavy-fermion superconductor PrOs$$_4$$Sb$$_{12}$$. The observed excitation clearly softens at a wave vector $$Q$$ = (1,0,0), which is the same as the modulation vector of the field-induced antiferro-quadrupolar ordering, and its intensity at $$Q$$ = (1,0,0) is smaller than that around the zone center. This result directly evidences that this excitonic behavior is derived mainly from nonmagnetic quadrupolar interactions. Furthermore, the narrowing of the linewidths of the excitations below the superconducting transition temperature indicates the close connection between the superconductivity and the excitons.

JAEA Reports

Program POD; A Computer code to calculate nuclear elastic scattering cross sections with the optical model and neutron inelastic scattering cross sections by the distorted-wave Born approximation

Ichihara, Akira; Kunieda, Satoshi; Chiba, Satoshi; Iwamoto, Osamu; Shibata, Keiichi; Nakagawa, Tsuneo; Fukahori, Tokio; Katakura, Junichi

JAERI-Data/Code 2005-004, 54 Pages, 2005/07

JAERI-Data-Code-2005-004.pdf:1.63MB

The computer code, POD, was developed to calculate angle-differential cross sections and analyzing powers for shape-elastic scattering for collisions of neutron or light ions with target nucleus. The cross sections are computed with the optical model. Angle-differential cross sections for neutron inelastic scattering can also be calculated with the distorted-wave Born approximation. The optical model potential parameters are the most essential inputs for those model computations. The cross sections and analyzing powers are obtained by using the existing local or global parameters. The parameters can also be inputted by users. In this report, the theoretical formulas, the computational methods, and the input parameters are explained. The sample inputs and outputs are also presented.

Journal Articles

Magnetic excitations in the heavy-fermion superconductor PrOs$$_4$$Sb$$_{12}$$

Raymond, S.*; Flouquet, J.*; Kuwahara, Keitaro*; Iwasa, Kazuaki*; Kogi, Masafumi*; Kaneko, Koji; Metoki, Naoto; Sugawara, Hitoshi*; Aoki, Yuji*; Sato, Hideyuki*

Physica B; Condensed Matter, 359-361, p.898 - 900, 2005/06

 Times Cited Count:2 Percentile:12.3(Physics, Condensed Matter)

The low lying magnetic excitations of the unconventional heavy fermion superconductor PrOs$$_4$$Sb$$_{12}$$ were studied by inelastic neutron scattering on single crystalline sample. The crystal field excitation first evidenced at 0.7 meV on powder samples is found to have a minimum of energy at the zone boundary corresponding to the wavevector of antiferro-quadrupolar instability. The evolution of the magnetic excitation spectrum under magnetic field confirms the singlet ground state.

Journal Articles

Lattice dynamics of methane hydrate

Yamauchi, Hiroki; Igawa, Naoki; Ishii, Yoshinobu

Proceedings of 5th International Conference on Gas Hydrates (ICGH-5), Volume 5, p.1615 - 1618, 2005/06

Inelastic neutron scattering experiments were carried out on powdered methane hydrate. In order to observe the precise spectra inelastic neutron scattering without the influence of incoherent contribution, the fully deuterated sample was used for the measurements. The relatively clear excitation peaks were observed at about 6.5 meV and 10 meV mainly corresponding to the transverse acoustic modes and exhibited only very little temperature dependence at 10 K and 100 K. On the other hand, the small shoulder found around 4 meV at 10 K showed apparent temperature dependence. The scattering intensity of this shoulder appeared to broaden and decrease at 100 K, which can be attributed to the increasing anharmonic contribution to the translational motion of the methane molecules encaged in the large cages.

Journal Articles

The Design of the neutron total scattering spectrometer for hydrogenous materials at J-PARC-JSNS

Suzuya, Kentaro; Kameda, Yasuo*; Otomo, Toshiya*; Yoshida, Koji*; Ito, Keiji*; Fukunaga, Toshiharu*; Misawa, Masakatsu*

Journal of Neutron Research, 13(1-3), p.123 - 128, 2005/03

The design, performance, philosophy, lessons learned and advantages of the neutron total scattering spectrometer for hydrogenous materials, FAST, under consideration for the J-PARC-JSNS, are described. In particular, novel instrumentation concept such as the small fractional scattered neutron flight path, $$gamma$$= L$$_{2}$$/(L$$_{1}$$+L$$_{2}$$), where L$$_{1}$$ is the incident flight path, moderator to sample, L$$_{2}$$ is the scattered neutron flight path from sample to detector, is presented and their expected performance at the JSNS is considered.

Journal Articles

CRYOPAD on the triple-axis spectrometer TAS-1 at JAERI

Takeda, Masayasu; Nakamura, Mitsutaka; Kakurai, Kazuhisa; Leli$`e$vre-Berna, E.*; Tasset, F.*; Regnault, L.-P.*

Physica B; Condensed Matter, 356(1-4), p.136 - 140, 2005/02

 Times Cited Count:16 Percentile:57.32(Physics, Condensed Matter)

It is now well known that CRYOPAD (CRYOgenic Polarization Analysis Device) is a powerful device which enables us to investigate the spherical changes of neutron-spin polarization in the scattering processes of magnetic materials. ILL and CEA-Grenoble, in the framework of EC/ENPI, and JAERI, in the framework of the MoU between ILL and ASRC JAERI, initiated to assemble three third generation CRYOPADs at ILL (CRYOPADUM project), optimized both for elastic and inelastic neutron scattering. One is installed on the ILL instrument D3 (Millennium Project) and the other on the CEA-Grenoble instrument IN22. The JAERI CRYOPADUM is installed on the triple-axis spectrometer TAS-1 at JRR-3 and is now in commissioning with powerful data acquisition software implanted from D3. We present the status of the CRYOPADUM on TAS-1 at JAERI and describe some of the planned experiments.

Journal Articles

High-energy resolution inelastic neutron scattering experiment on magnetic fracton dispersion in near-percolating three-dimensional Heisenberg antiferromagnet, RbMn$$_{0,4}$$Mg$$_{0.6}$$F$$_{3}$$

Ito, Shinichi*; Kajimoto, Ryoichi; Adams, M. A.*

Journal of the Physical Society of Japan, 74(1), p.279 - 282, 2005/01

 Times Cited Count:3 Percentile:27.56(Physics, Multidisciplinary)

Magnetic fractons in the near-percolating three-dimensional (3D) Heisenberg antiferromagnet, RbMn$$_{0.4}$$Mg$$_{0.6}$$F$$_{3}$$, have been studied using inelastic neutron scattering with high energy resolution ($$Delta E=17.5 mu$$eV) and at low temperature ($$T=1.5$$ K). It is demonstrated that the fractons follow the dispersion relation of $$q^z$$ (q being the wave number). The observed exponent, $$z=2.5$$, is in good agreement with the fractal dimension of the 3D system ($$D_f=2.48$$), as predicted by theory.

Journal Articles

Phonon anomaly on Na$$_x$$HfNCl superconductors with ${it T}$$$_c$$=22 K

Shamoto, Shinichi; Hirai, Atsuo*; Yamanaka, Shoji*; Aso, Naofumi*; Kajitani, Tsuyoshi*

Journal of Neutron Research, 12(4), p.295 - 300, 2004/12

Inelastic neutron scattering measurements have been performed on superconducting Na$$_x$$HfNCl powder samples with x=0.27 and 0.38 (T$$_c$$ =22 K). We have observed several temperature dependent phonon anomalies, e.g., at E=15, 29, 76, and 81 meV for the former sample. A phonon peak with E=14.5 meV at Q=6 $AA $^{-1}$$ increases for both samples with decreasing temperature below T=40 K, which is much higher than T$$_c$$. The phonon peak is assigned to an ab-plane vibrational mode, E$$_u$$, of chlorine and hafnium atoms, which strongly modifies the electronic band structure. The phonon anomaly is discussed in terms of carrier inhomogeneity.

Journal Articles

Neutron science and high pressure; Inelastic neutron scattering associated with pressure-induced phase transition

Fujii, Yasuhiko

Koatsuryoku No Kagaku To Gijutsu, 14(2), p.113 - 118, 2004/05

no abstracts in English

Journal Articles

Inelasticity effect on neutron scattering intensities of the null-H$$_{2}$$O

Kameda, Yasuo*; Sasaki, Motoya*; Usuki, Takeshi*; Otomo, Toshiya*; Ito, Keiji*; Suzuya, Kentaro; Fukunaga, Toshiharu*

Journal of Neutron Research, 11(3), p.153 - 163, 2003/09

We describe results of time-of-flight (TOF) neutron diffraction of the liquid water null-H$$_{2}$$O in order to investigate the effect of both the scattering angle and the neutron flight path ratio to the observed self-scattering intensities. An empirical inelasticity correction procedure is proposed using the self-scattering intensity observed for the null-H$$_{2}$$O.

Journal Articles

High efficiency indirect geometory crystal analyzer TOF spectrometer; DYANA dedicated to biology, planning in JSNS

Shibata, Kaoru; Tamura, Itaru; Soyama, Kazuhiko; Arai, Masatoshi; Middendorf, H. D.*; Niimura, Nobuo

Proceedings of ICANS-XVI, Volume 1, p.351 - 354, 2003/07

In this research report we describe the design of DYANA, a new neutron spectrometer dedicated for biology, biomaterials, and related soft-matter studies, which will be installed in the material and life science experimental facility project at the JAERI Tokai establishment. The DYANA spectrometer is an indirect-geometry crystal-analyzer instrument and its energy and momentum transfer range are from several 10$$mu$$eV to several meV and from 0.1$$AA ^{-1}$$ to several $$AA ^{-1}$$ , respectively. These specifications will become possible to do the study of protein dynamics analysis.

JAEA Reports

A Design of neutron inelastic scattering spectrometer for protein dynamics analysis: DYANA

Shibata, Kaoru; Tamura, Itaru; Soyama, Kazuhiko; Arai, Masatoshi; Niimura, Nobuo

JAERI-Research 2002-036, 30 Pages, 2003/03

JAERI-Research-2002-036.pdf:1.79MB

In this research report we describe the design of DYANA, a new neutron spectrometer dedicated for biology, biomaterials, and related soft-matter studies, which will be installed in the material and life science experimental facility project at the JAERI Tokai establishment. The DYANA spectrometer is an indirect-geometry crystal-analyzer instrument and it's energy and momentum transfer range are from several 10$$mu$$eV to several meV and from 0.1$$AA ^{-1}$$ to several $$AA ^{-1}$$ , respectively. These specifications will become possible to do the study of protein dynamics analysis.

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