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208 results on '"Ohishi, Kazuki"'

52. How Li diffusion in spinel Li[Ni1/2Mn3/2]O4 is seen with μ±SR.

Author

Sugiyama, Jun, Ohishi, Kazuki, Forslund, Ola Kenji, Månsson, Martin, Cottrell, Stephen P., Hillier, Adrian D., and Ishida, Katsuhiko

Subjects
MUON spin rotation, MUONS, SPINEL, DIFFUSION coefficients, RANDOM walks, STRESS relaxation (Mechanics), IONIC conductivity, POLARONS
Abstract

The diffusive behavior in a spinel-type Li+ ion battery material, Li[Ni1/2Mn3/2]O4, has been studied with positive and negative muon spin rotation and relaxation (μ±SR) measurements in the temperature range between 200 and 400 K using a powder sample. The implanted μ+ locates at an interstitial site near O2− ion so as to form a O–H like bond, while the implanted μ− is mainly captured by an oxygen nucleus, resulting in the formation of muonic oxygen. This means that local magnetic environments in Li[Ni1/2Mn3/2]O4 were investigated from the two different sites in the lattice, i.e., one is an interstitial site for μ+SR and the other is an oxygen site for μ−SR. Since both μ+SR and μ−SR detected an increase in the fluctuation rate of a nuclear magnetic field for temperatures above 200 K, the origin of this increase is clearly confirmed as Li diffusion. Assuming a random walk process with the hopping of thermally activated Li+ between a regular Li site and the nearest neighboring vacant octahedral sites, a self-diffusion coefficient of Li+ was found to range above 10−11 cm2/s at temperatures above 250 K with an activation energy of about 0.06 eV. [ABSTRACT FROM AUTHOR]

Published
2022
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55. Structural Transition with a Sharp Change in the Electrical Resistivity and Spin–Orbit Mott Insulating State in a Rhenium Oxide, Sr3Re2O9

Author

Urushihara, Daisuke, primary, Asaka, Toru, additional, Fukuda, Koichiro, additional, Nakayama, Masanobu, additional, Nakahira, Yuki, additional, Moriyoshi, Chikako, additional, Kuroiwa, Yoshihiro, additional, Forslund, Ola K., additional, Matsubara, Nami, additional, Månsson, Martin, additional, Papadopoulos, Konstantinos, additional, Sassa, Yasmine, additional, Ohishi, Kazuki, additional, Sugiyama, Jun, additional, Matsushita, Yoshitaka, additional, and Sakurai, Hiroya, additional

Published
2021
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59. Magnetization process of cubic Fe3O4 submicron particles studied by polarized small-angle neutron scattering.

Author

Nomura, Eiji, Chiba, Momoko, Matsuo, Sakoto, Noda, Chiaki, Kobayashi, Satoru, Manjanna, Jayappa, Kawamura, Yukihiko, Ohishi, Kazuki, Hiroi, Kosuke, and Suzuki, Jun-ichi

Subjects
SMALL-angle neutron scattering, SPHEROMAKS, MAGNETIC anisotropy, MAGNETIZATION, MAGNETIC fields, COERCIVE fields (Electronics)
Abstract

We report results of polarized small-angle neutron scattering (SANS) experiments at T = 10 K and 300 K for cubic Fe3O4 submicron-sized particles, where formation of a complex spin vortex is expected. Magnetic SANS intensities of magnetization components in the direction perpendicular and parallel to the magnetic field were observed to change significantly at around the coercivity. Magnetization components parallel to the field minimizes around the coercivity both at T = 10 K and 300 K, whereas those perpendicular to the magnetic field maximizes near the coercivity and the maximum value differ greatly, depending on the temperature. Based on results of micromagnetic simulations, the observed SANS intensities were interpreted as due to magnetic structural changes from a flower to a spin vortex state and gradual tilting of a vortex core from the external field to magnetocrystalline anisotropy axes at low fields. [ABSTRACT FROM AUTHOR]

Published
2022
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61. Magnetic Structure of a Chiral Magnet DyNi3Al9

Author

Iba, Kenshirou, primary, Matsumura, Takeshi, additional, Nakao, Akiko, additional, Ishikawa, Yoshihisa, additional, Ohishi, Kazuki, additional, Kiyanagi, Ryoji, additional, Kousaka, Yusuke, additional, and Ohara, Shigeo, additional

Published
2020
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62. Proximity coupling of superconducting nanograins with fractal distributions

Author

Uchino, Takashi, primary, Teramachi, Nanami, additional, Matsuzaki, Ryosuke, additional, Tsushima, Emi, additional, Fujii, Shusuke, additional, Seto, Yusuke, additional, Takahashi, Kazuyuki, additional, Mori, Takao, additional, Adachi, Yutaka, additional, Nagashima, Yukihito, additional, Sakaguchi, Yoshifumi, additional, Ohishi, Kazuki, additional, Koda, Akihiro, additional, Sakurai, Takahiro, additional, and Ohta, Hitoshi, additional

Published
2020
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63. How Li diffusion in spinel Li[Ni1/2Mn3/2]O4is seen with μ±SR

Author

Sugiyama, Jun, Ohishi, Kazuki, Forslund, Ola Kenji, Månsson, Martin, Cottrell, Stephen P., Hillier, Adrian D., and Ishida, Katsuhiko

Abstract

The diffusive behavior in a spinel-type Li+ion battery material, Li[Ni1/2Mn3/2]O4, has been studied with positive and negative muon spin rotation and relaxation (μ±SR) measurements in the temperature range between 200 and 400 K using a powder sample. The implanted μ+locates at an interstitial site near O2−ion so as to form a O–H like bond, while the implanted μ−is mainly captured by an oxygen nucleus, resulting in the formation of muonic oxygen. This means that local magnetic environments in Li[Ni1/2Mn3/2]O4were investigated from the two different sites in the lattice, i.e., one is an interstitial site for μ+SR and the other is an oxygen site for μ−SR. Since both μ+SR and μ−SR detected an increase in the fluctuation rate of a nuclear magnetic field for temperatures above 200 K, the origin of this increase is clearly confirmed as Li diffusion. Assuming a random walk process with the hopping of thermally activated Li+between a regular Li site and the nearest neighboring vacant octahedral sites, a self-diffusion coefficient of Li+was found to range above 10−11cm2/s at temperatures above 250 K with an activation energy of about 0.06 eV.

Published
2022
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64. Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites1

Author

Noda, Yohei, Koizumi, Satoshi, Masui, Tomomi, Mashita, Ryo, Kishimoto, Hiroyuki, Yamaguchi, Daisuke, Kumada, Takayuki, Takata, Shin-ichi, Ohishi, Kazuki, and Suzuki, Jun-ichi

Subjects
Condensed Matter::Soft Condensed Matter, dynamic nuclear polarization, Condensed Matter::Materials Science, small-angle neutron scattering (SANS), Nuclear Theory, nanocomposites, contrast variation, ternary mixtures, Nuclear Experiment, Research Papers
Abstract

Contrast variation small-angle neutron scattering by dynamic nuclear polarization is applied to industrial multi-component nanocomposites., Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization (P H). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping its q dependence for P H = −35% or P H = 40%, respectively. The q behaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at low q (∼0.01 Å−1) varied as a quadratic function of P H and indicated a minimum value at P H = 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at high q (∼0.3 Å−1) decreased with increasing P H, which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), the q behaviour of SANS was varied by changing P H. At P H = −35%, the scattering maxima originating from the form factor of SP prevailed, whereas at P H = 29% and P H = 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according to q −3.6, which is consistent with the results for the SBR/CP mixture.

Published
2016

68. Development of spin‐contrast‐variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms.

Author

Miura, Daisuke, Kumada, Takayuki, Sekine, Yurina, Motokawa, Ryuhei, Nakagawa, Hiroshi, Oba, Yojiro, Ohhara, Takashi, Takata, Shin-ichi, Hiroi, Kosuke, Morikawa, Toshiaki, Kawamura, Yukihiko, Ohishi, Kazuki, Suzuki, Jun-ichi, Miyachi, Yoshiyuki, and Iwata, Takahiro

Subjects
HYDROGEN atom, FACTOR structure, NEUTRONS, POWDERS, GLUTAMIC acid, NEUTRON diffraction
Abstract

A spin‐contrast‐variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, i.e. the contribution of hydrogen atoms to a crystal's structure factor, has been developed. Crystals of l‐glutamic acid were dispersed in a d‐polystyrene matrix containing 4‐methacryloyloxy‐2,2,6,6,‐tetramethyl‐1‐piperidinyloxy to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton‐polarization‐dependent intensities. This technique is expected to enable analyses of the structures of hydrogen‐containing materials that are difficult to determine with conventional powder diffractometry. [ABSTRACT FROM AUTHOR]

Published
2021
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76. Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex II: Neutron Scattering Instruments

Author

Nakajima, Kenji, primary, Kawakita, Yukinobu, additional, Itoh, Shinichi, additional, Abe, Jun, additional, Aizawa, Kazuya, additional, Aoki, Hiroyuki, additional, Endo, Hitoshi, additional, Fujita, Masaki, additional, Funakoshi, Kenichi, additional, Gong, Wu, additional, Harada, Masahide, additional, Harjo, Stefanus, additional, Hattori, Takanori, additional, Hino, Masahiro, additional, Honda, Takashi, additional, Hoshikawa, Akinori, additional, Ikeda, Kazutaka, additional, Ino, Takashi, additional, Ishigaki, Toru, additional, Ishikawa, Yoshihisa, additional, Iwase, Hiroki, additional, Kai, Tetsuya, additional, Kajimoto, Ryoichi, additional, Kamiyama, Takashi, additional, Kaneko, Naokatsu, additional, Kawana, Daichi, additional, Ohira-Kawamura, Seiko, additional, Kawasaki, Takuro, additional, Kimura, Atsushi, additional, Kiyanagi, Ryoji, additional, Kojima, Kenji, additional, Kusaka, Katsuhiro, additional, Lee, Sanghyun, additional, Machida, Shinichi, additional, Masuda, Takatsugu, additional, Mishima, Kenji, additional, Mitamura, Koji, additional, Nakamura, Mitsutaka, additional, Nakamura, Shoji, additional, Nakao, Akiko, additional, Oda, Tatsuro, additional, Ohhara, Takashi, additional, Ohishi, Kazuki, additional, Ohshita, Hidetoshi, additional, Oikawa, Kenichi, additional, Otomo, Toshiya, additional, Sano-Furukawa, Asami, additional, Shibata, Kaoru, additional, Shinohara, Takenao, additional, Soyama, Kazuhiko, additional, Suzuki, Jun-ichi, additional, Suzuya, Kentaro, additional, Takahara, Atsushi, additional, Takata, Shin-ichi, additional, Takeda, Masayasu, additional, Toh, Yosuke, additional, Torii, Shuki, additional, Torikai, Naoya, additional, Yamada, Norifumi, additional, Yamada, Taro, additional, Yamazaki, Dai, additional, Yokoo, Tetsuya, additional, Yonemura, Masao, additional, and Yoshizawa, Hideki, additional

Published
2017
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77. Energy-resolved small-angle neutron scattering from steel

Author

Oba, Yojiro, primary, Morooka, Satoshi, additional, Ohishi, Kazuki, additional, Suzuki, Jun-ichi, additional, Takata, Shin-ichi, additional, Sato, Nobuhiro, additional, Inoue, Rintaro, additional, Tsuchiyama, Toshihiro, additional, Gilbert, Elliot Paul, additional, and Sugiyama, Masaaki, additional

Published
2017
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82. Demonstration Study of Small-Angle Polarized Neutron Scattering Using Polarized 3He Neutron Spin Filter

Author

Kira, Hiroshi, primary, Hayashida, Hirotoshi, additional, Iwase, Hiroki, additional, Ohishi, Kazuki, additional, Suzuki, Jun-ichi, additional, Oku, Takayuki, additional, Sakai, Kenji, additional, Hiroi, Kosuke, additional, Takata, Shin-ichi, additional, Ino, Takashi, additional, Ohoyama, Kenji, additional, Ohkawara, Manabu, additional, Shinohara, Takenao, additional, Kakurai, Kazuhisa, additional, Aizawa, Kazuya, additional, and Arai, Masatoshi, additional

Published
2015
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83. The Design and q Resolution of the Small and Wide Angle Neutron Scattering Instrument (TAIKAN) in J-PARC

Author

Takata, Shin-ichi, primary, Suzuki, Jun-ichi, additional, Shinohara, Takenao, additional, Oku, Takayuki, additional, Tominaga, Taiki, additional, Ohishi, Kazuki, additional, Iwase, Hiroki, additional, Nakatani, Takeshi, additional, Inamura, Yasuhiro, additional, Ito, Takayoshi, additional, Suzuya, Kentaro, additional, Aizawa, Kazuya, additional, Arai, Masatoshi, additional, Otomo, Toshiya, additional, and Sugiyama, Masaaki, additional

Published
2015
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89. Chiral Magnetic Soliton Lattice in MnSi

Author

Kousaka, Yusuke, primary, Ikeda, Naoki, additional, Ogura, Takahiro, additional, Yoshii, Toha, additional, Akimitsu, Jun, additional, Ohishi, Kazuki, additional, Suzuki, Jun-ichi, additional, Hiraka, Haruhiko, additional, Miyagawa, Marina, additional, Nishihara, Sadafumi, additional, Inoue, Katsuya, additional, and Kishine, Jun-ichiro, additional

Published
2014
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90. Development of 3He Neutron Spin Filter for the Application at an Intense Pulsed Neutron Source Facility

Author

Oku, Takayuki, primary, Kira, Hiroshi, additional, Hayashida, Hirotoshi, additional, Sakai, Kenji, additional, Hiroi, Kosuke, additional, Shinohara, Takenao, additional, Ino, Takashi, additional, Ohkawara, Manabu, additional, Ohoyama, Kenji, additional, Takata, Shin-ichi, additional, Ohishi, Kazuki, additional, Iwase, Hiroki, additional, Miyata, Noboru, additional, Akutsu, Kazuhiro, additional, Sakaguchi, Yoshifumi, additional, Takeda, Masayasu, additional, Suzuki, Jun-ichi, additional, Aizawa, Kazuya, additional, Arai, Masatoshi, additional, and Kakurai, Kazuhisa, additional

Published
2014
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91. The Small and Wide Angle Neutron Scattering Instrument TAIKAN at J-PARC

Author

Takata, Shin-ichi, primary, Suzuki, Jun-ichi, additional, Ohishi, Kazuki, additional, Iwase, Hiroki, additional, Shinohara, Takenao, additional, Oku, Takayuki, additional, Tominaga, Taiki, additional, Inamura, Yasuhiro, additional, Ito, Takayoshi, additional, Nakatani, Takeshi, additional, Suzuya, Kentaro, additional, Aizawa, Kazuya, additional, Otomo, Toshiya, additional, Sugiyama, Masaaki, additional, and Arai, Masatoshi, additional

Published
2014
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92. Magnetic Ground State of Pr$_{0.89}$LaCe$_{0.11}$CuO$_{4+��-��}$ with Varied Oxygen Depletion Probed by Muon Spin Relaxation

Author

Kadono, Ryosuke, Ohishi, Kazuki, Koda, Akihiro, Higemoto, Wataru, Kojima, Kenji M., Kuroshima, Shin-ichi, Fujita, Masaki, and Yamada, Kazyoshi

Subjects
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el), Condensed Matter::Superconductivity, FOS: Physical sciences, Condensed Matter::Strongly Correlated Electrons
Abstract

The magnetic ground state of an electron-doped cuprate superconductor Pr$_{1-x}$LaCe$_x$CuO$_{4+��-��}$ ($x=0.11, ��\simeq0.04$) has been studied by means of muon spin rotation/relaxation (\msr) over a wide variety of oxygen depletion, $0.03\le��\le0.12$. Appearance of weak random magnetism over entire crystal volume has been revealed by a slow exponential relaxation. The absence of $��$-dependence for the random magnetism and the multiplet pattern of muon Knight shift at higher fields strongly suggest that the random moments are associated with excited Pr$^{3+}$ ions under crystal electric field., 6 pages, 4 figures, submitted to J. Phys. Soc. Jpn

Published
2003
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94. Flux-line lattice state in FeAs-based superconductor KFe2As2

Author

Ohishi, Kazuki, primary, Ishii, Yasuyuki, additional, Watanabe, Isao, additional, Fukazawa, Hideto, additional, Saito, Taku, additional, Kohori, Yoh, additional, Kihou, Kunihiro, additional, Lee, Chul-Ho, additional, Kito, Hijiri, additional, Iyo, Akira, additional, and Eisaki, Hiroshi, additional

Published
2012
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97. Magnetic Penetration Depth in the FeAs-Based Superconductor KFe2As2

Author

Ohishi, Kazuki, primary, Ishii, Yasuyuki, additional, Watanabe, Isao, additional, Fukazawa, Hideto, additional, Saito, Taku, additional, Kohori, Yoh, additional, Kihou, Kunihiro, additional, Lee, Chul-Ho, additional, Kito, Hijiri, additional, Iyo, Akira, additional, and Eisaki, Hiroshi, additional

Published
2012
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98. Magnetic and diffusive nature of LiFePO4investigated by muon spin rotation and relaxation

Author

Sugiyama, Jun, primary, Nozaki, Hiroshi, additional, Harada, Masashi, additional, Kamazawa, Kazuya, additional, Ofer, Oren, additional, Månsson, Martin, additional, Brewer, Jess H., additional, Ansaldo, Eduardo J., additional, Chow, Kim H., additional, Ikedo, Yutaka, additional, Miyake, Yasuhiro, additional, Ohishi, Kazuki, additional, Watanabe, Isao, additional, Kobayashi, Genki, additional, and Kanno, Ryoji, additional

Published
2011
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