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Journal Articles

Quantum critical behavior of the hyperkagome magnet Mn$$_3$$CoSi

Yamauchi, Hiroki; Sari, D. P.*; Yasui, Yukio*; Sakakura, Terutoshi*; Kimura, Hiroyuki*; Nakao, Akiko*; Ohara, Takashi; Honda, Takashi*; Kodama, Katsuaki; Igawa, Naoki; et al.

Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02

Journal Articles

Local structural changes in V-Ti-Cr alloy hydrides with hydrogen absorption/desorption cycling

Ikeda, Kazutaka*; Sashida, Sho*; Otomo, Toshiya*; Oshita, Hidetoshi*; Honda, Takashi*; Hawai, Takafumi*; Saito, Hiraku*; Ito, Shinichi*; Yokoo, Tetsuya*; Sakaki, Koji*; et al.

International Journal of Hydrogen Energy, 51(Part A), p.79 - 87, 2024/01

 Times Cited Count:0 Percentile:0.01(Chemistry, Physical)

Journal Articles

Quasielastic neutron scattering probing H$$^{-}$$ dynamics in the H$$^{-}$$ conductors LaH$$_{3-2x}$$O$$_{x}$$

Tamatsukuri, Hiromu; Fukui, Keiga*; Iimura, Soshi*; Honda, Takashi*; Tada, Tomofumi*; Murakami, Yoichi*; Yamaura, Junichi*; Kuramoto, Yoshio*; Sagayama, Hajime*; Yamada, Takeshi*; et al.

Physical Review B, 107(18), p.184114_1 - 184114_8, 2023/05

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

Journal Articles

Hydrogen vibration excitations of ZrH$$_{1.8}$$ and TiH$$_{1.84}$$ up to 21 GPa by incoherent inelastic neutron scattering

Hattori, Takanori; Nakamura, Mitsutaka; Iida, Kazuki*; Machida, Akihiko*; Sano, Asami; Machida, Shinichi*; Arima, Hiroshi*; Oshita, Hidetoshi*; Honda, Takashi*; Ikeda, Kazutaka*; et al.

Physical Review B, 106(13), p.134309_1 - 134309_9, 2022/10

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

Hydrogen vibration excitations of fluorite-type ZrH$$_{1.8}$$ and TiH$$_{1.84}$$ were investigated up to 21 GPa and 4 GPa, respectively, by incoherent inelastic neutron scattering experiments. The first excitation energies increased with pressure, as described by the equations $$E_1$$(meV) = 141.4(2) + 1.02(2)$$P$$(GPa) and $$E_1$$(meV) = 149.4(1) + 1.21(8)$$P$$(GPa) for ZrH$$_{1.8}$$ and TiH$$_{1.84}$$, respectively. Coupling with pressure dependence of lattice parameters, the relations between metal-hydrogen distance ($$d_{M-H}$$) and $$E_1$$ are found to be well described by the equations $$E_1$$(meV) = 1.62(9)$$times$$ 10$$^3$$ $$d_{M-H}^{-3.31(8)}$$($AA) and $E_1$$(meV) = 1.47(21)$$times$$ 10$$^3$$ $$d_{M-H}^{-3.5(2)}$$(AA), respectively. The slopes of these curves are much steep compared to the previously reported trend in various fluorite-type metal hydrides at ambient pressure. The hydrogen wave function spreading showed that the local potential field for a hydrogen atom shrinks more intensively than the tetrahedral site. These behavior is likely caused by the rigid metal ion core and the resulting confinement of the hydrogen atom in the narrower potential field at high pressures.

Journal Articles

Magnetic structure of short-range ordering in intermetallic antiferromagnet Mn$$_3$$RhSi

Kodama, Katsuaki; Honda, Takashi*; Yamauchi, Hiroki; Shamoto, Shinichi*; Ikeda, Kazutaka*; Otomo, Toshiya*

Journal of the Physical Society of Japan, 90(7), p.074710_1 - 074710_7, 2021/07

 Times Cited Count:1 Percentile:15.97(Physics, Multidisciplinary)

Journal Articles

Magnetic pair distribution function of spin-glass system Mn$$_{0.5}$$Fe$$_{0.5}$$TiO$$_3$$

Kodama, Katsuaki; Honda, Takashi*; Ikeda, Kazutaka*; Shamoto, Shinichi; Otomo, Toshiya*

JPS Conference Proceedings (Internet), 33, p.011059_1 - 011059_6, 2021/03

Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 Times Cited Count:11 Percentile:78.21(Instruments & Instrumentation)

Journal Articles

Strong lattice anharmonicity exhibited by the high-energy optical phonons in thermoelectric material

Wu, P.*; Fan, F.-R.*; Hagihara, Masato*; Kofu, Maiko; Peng, K.*; Ishikawa, Yoshihisa*; Lee, S.*; Honda, Takashi*; Yonemura, Masao*; Ikeda, Kazutaka*; et al.

New Journal of Physics (Internet), 22(8), p.083083_1 - 083083_9, 2020/08

 Times Cited Count:9 Percentile:57.85(Physics, Multidisciplinary)

Thermoelectric material SnSe has aroused world-wide interests in the past years, and its inherent strong lattice anharmonicity is regarded as a crucial factor for its outstanding thermoelectric performance. However, the understanding of lattice anharmonicity in SnSe system remains inadequate, especially regarding how phonon dynamics are affected by this behavior. In this work, we present a comprehensive study of lattice dynamics on Na$$_{0.003}$$Sn$$_{0.997}$$Se$$_{0.9}$$S$$_{0.1}$$ by means of neutron total scattering, inelastic neutron scattering, Raman spectroscopy as well as frozen-phonon calculations. Lattice anharmonicity is evidenced by pair distribution function, inelastic neutron scattering and Raman measurements. By separating the effects of thermal expansion and multi-phonon scattering, we found that the latter is very significant in high-energy optical phonon modes. The strong temperature-dependence of these phonon modes indicate the anharmonicity in this system. Moreover, our data reveals that the linewidths of high-energy optical phonons become broadened with mild doping of sulfur. Our studies suggest that the thermoelectric performance of SnSe could be further enhanced by reducing the contributions of high-energy optical phonon modes to the lattice thermal conductivity via phonon engineering.

Journal Articles

Quantum dynamics of hydrogen in the iron-based superconductor LaFeAsO$$_{0.9}$$D$$_{0.1}$$ measured with inelastic neutron spectroscopy

Yamaura, Junichi*; Hiraka, Haruhiro*; Iimura, Soshi*; Muraba, Yoshinori*; Bang, J.*; Ikeuchi, Kazuhiko*; Nakamura, Mitsutaka; Inamura, Yasuhiro; Honda, Takashi*; Hiraishi, Masatoshi*; et al.

Physical Review B, 99(22), p.220505_1 - 220505_6, 2019/06

AA2019-0126.pdf:0.9MB

 Times Cited Count:3 Percentile:16.02(Materials Science, Multidisciplinary)

Inelastic neutron scattering was performed for an iron-based superconductor, where most of D (deuterium) replaces oxygen, while a tiny amount goes into interstitial sites. By first-principle calculation, we characterize the interstitial sites for D (and for H slightly mixed) with four equivalent potential minima. Below the superconducting transition temperature Tc = 26 K, new excitations emerge in the range 5-15 meV, while they are absent in the reference system LaFeAsO$$_{0.9}$$F$$_{0.1}$$. The strong excitations at 14.5 meV and 11.1 meV broaden rapidly around 15 K and 20 K, respectively, where each energy becomes comparable to twice of the superconducting gap. The strong excitations are ascribed to a quantum rattling, or a band motion of hydrogen, which arises only if the number of potential minima is larger than two.

Journal Articles

Nanoscale ice-type structural fluctuation in spinel titanates

Torigoe, Shuhei*; Hattori, Takayuki*; Kodama, Katsuaki; Honda, Takashi*; Sagayama, Hajime*; Ikeda, Kazutaka*; Otomo, Toshiya*; Nitani, Hiroaki*; Abe, Hitoshi*; Murakawa, Hiroshi*; et al.

Physical Review B, 98(13), p.134443_1 - 134443_7, 2018/10

 Times Cited Count:11 Percentile:48.71(Materials Science, Multidisciplinary)

Journal Articles

Elastic and dynamical structural properties of La and Mn-doped SrTiO$$_{3}$$ studied by neutron scattering and their relation with thermal conductivities

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Murai, Naoki; Shamoto, Shinichi; Honda, Takashi*; Ikeda, Kazutaka*; Otomo, Toshiya*; Hata, Hiroto*; Eto, Takahiro*; Noda, Masaaki*; et al.

Scientific Reports (Internet), 8(1), p.9651_1 - 9651_8, 2018/06

 Times Cited Count:6 Percentile:30.02(Multidisciplinary Sciences)

Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Structural investigation of magnetocapacitive SmMnO$$_3$$

Maeda, Hiroki*; Ishiguro, Yuki*; Honda, Takashi*; Jung, J.-S.*; Michimura, Shinji*; Inami, Toshiya; Kimura, Tsuyoshi*; Wakabayashi, Yusuke*

Journal of the Ceramic Society of Japan, 121(3), p.265 - 267, 2013/03

 Times Cited Count:5 Percentile:30.35(Materials Science, Ceramics)

Structural deformation of a magnetocapacitive material SmMnO$$_3$$ was studied by X-ray diffraction measurement in a magnetic field. This antiferromagnetic material shows a jump in dielectric constant at 9 K only when a magnetic field of a few tesla is applied. In-field X-ray diffraction measurements clarified that there is no sudden change in structure that involves atomic displacement within the c-plane in Pbnm notation, while the antiferromagnetic phase transition at 60 K gives rise to a noticeable rotation of the MnO$$_6$$ octahedra. This rotation occurs to maximize the energy gain through the exchange interaction.

Oral presentation

Local magnetic structure of spin-glass material Mn$$_{0.5}$$Fe$$_{0.5}$$TiO$$_3$$ observed by magnetic pair distribution function

Kodama, Katsuaki; Honda, Takashi*; Ikeda, Kazutaka*; Shamoto, Shinichi; Otomo, Toshiya*

no journal, , 

no abstracts in English

Oral presentation

Observation of short range spin correlation in spin glass phase of Mn$$_{0.5}$$Fe$$_{0.5}$$TiO$$_3$$ by magnetic pair distribution function (mPDF)

Kodama, Katsuaki; Honda, Takashi*; Ikeda, Kazutaka*; Shamoto, Shinichi; Otomo, Toshiya*

no journal, , 

no abstracts in English

Oral presentation

Magnetic pair distribution function (mPDF) analysis at neutron total scattering spectrometer NOVA

Kodama, Katsuaki; Honda, Takashi*; Ikeda, Kazutaka*; Shamoto, Shinichi; Otomo, Toshiya*

no journal, , 

no abstracts in English

Oral presentation

Magnetic structural analysis on metallic magnet Mn$$_3$$RhSi using magnetic pair distribution function

Kodama, Katsuaki; Honda, Takashi*; Yamauchi, Hiroki; Shamoto, Shinichi; Ikeda, Kazutaka*; Otomo, Toshiya*

no journal, , 

no abstracts in English

Oral presentation

Development and application of magnetic Pair Distribution Function (mPDF) analysis

Kodama, Katsuaki; Honda, Takashi*; Ikeda, Kazutaka*; Shamoto, Shinichi; Otomo, Toshiya*

no journal, , 

Oral presentation

Elastic and dynamical structural properties of La and Mn-doped SrTiO$$_{3}$$ studied by neutron scattering and their relation with thermal conductivities

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Murai, Naoki; Shamoto, Shinichi; Honda, Takashi*; Ikeda, Kazutaka*; Otomo, Toshiya*; Hata, Hiroto*; Eto, Takahiro*; Noda, Masaaki*; et al.

no journal, , 

Oral presentation

Magnetic PDF analysis on metallic magnet Mn$$_3$$RhSi

Kodama, Katsuaki; Honda, Takashi*; Yamauchi, Hiroki; Shamoto, Shinichi; Ikeda, Kazutaka*; Otomo, Toshiya*

no journal, , 

no abstracts in English

29 (Records 1-20 displayed on this page)