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Journal Articles

Origin of magnetovolume effect in a cobaltite

Miao, P.*; Tan, Z.*; Lee, S. H.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Yonemura, Masao*; Koda, Akihiro*; Komatsu, Kazuki*; Machida, Shinichi*; Sano, Asami; et al.

Physical Review B, 103(9), p.094302_1 - 094302_18, 2021/03

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

The layered perovskite PrBaCo$$_{2}$$O$$_{5.5}$$ demonstrates a strong negative thermal expansion (NTE) which holds potential for being fabricated into composites with zero thermal expansion. The NTE was found to be intimately associated with the spontaneous magnetic ordering, known as magneto-volume effect (MVE). Here we report with compelling evidences that the continuous-like MVE in PrBaCo$$_{2}$$O$$_{5.5}$$ is intrinsically of discontinuous character, originating from an magnetoelectric transition from an antiferromagnetic insulating large-volume (AFILV) phase to a ferromagnetic less-insulating small-volume (FLISV) phase. Furthermore, the magnetoelectric effect (ME) shows high sensitivity to multiple external stimuli such as temperature, carrier doping, hydrostatic pressure, magnetic field etc. In contrast to the well-known ME such as colossal magnetoresistance and multi-ferroic effect which involve symmetry breaking of crystal structure, the ME in the cobaltite is purely isostructural. Our discovery provides a new path way to realizing the ME as well as the NTE, which may find applications in new techniques.

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:2 Percentile:51.78(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

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.

JAEA Reports

Proceedings of the 21st Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XXI); Sep. 29 - Oct.3, 2014, Ibaraki Prefectural Center, Mito, Japan

Oku, Takayuki; Nakamura, Mitsutaka; Sakai, Kenji; Teshigawara, Makoto; Hideki, Tatsumoto*; Yonemura, Masao*; Suzuki, Junichi*; Arai, Masatoshi*

JAEA-Conf 2015-002, 660 Pages, 2016/02

JAEA-Conf-2015-002.pdf:168.34MB

The twenty first meeting of the International Collaboration on Advanced Neutron Source (ICANS-XXI) was held at Ibaraki Prefectural Culture Center in Mito from 29 September to 3 October 2014. It was hosted by Japan Atomic Energy Agency (JAEA), High Energy Accelerator Research Organization (KEK) and Comprehensive Research Organization for Science and Society (CROSS). In the meeting, new science and technology in the new era with the high power neuron sources were discussed in mostly "workshop style" sessions. In each session, various kinds of issues related to not only the hardware, but also the software and even radiation safety were discussed with the keyword of "INTERFACE". More than 200 Papers were presented in the meeting and 72 contributed papers are compiled in the proceedings.

Journal Articles

Direct observation of fast lithium-ion diffusion in a superionic conductor; Li$$_{7}$$P$$_{3}$$S$$_{11}$$ metastable crystal

Mori, Kazuhiro*; Enjuji, Keigo*; Murata, Shun*; Shibata, Kaoru; Kawakita, Yukinobu; Yonemura, Masao*; Onodera, Yohei*; Fukunaga, Toshiharu*

Physical Review Applied (Internet), 4(5), p.054008_1 - 054008_6, 2015/11

 Times Cited Count:22 Percentile:72.73(Physics, Applied)

no abstracts in English

Journal Articles

Transformation strain and texture evolution during diffusional phase transformation of low alloy steels studied by neutron diffraction

Xu, P. G.; Tomota, Yo*; Vogel, S. C.*; Suzuki, Tetsuya*; Yonemura, Masao*; Kamiyama, Takashi*

Reviews on Advanced Materials Science, 33(5), p.389 - 395, 2013/08

Journal Articles

Oscillatory diffuse scattering study by time-of-flight neutron scattering

Basar, K.*; Xianglian*; Siagian, S.*; Sakuma, Takashi*; Takahashi, Haruyuki*; Yonemura, Masao*; Kamiyama, Takashi*; Ishigaki, Toru*; Igawa, Naoki

Physica B; Condensed Matter, 403(17), p.2557 - 2560, 2008/08

 Times Cited Count:2 Percentile:12.76(Physics, Condensed Matter)

Diffuse scattering is an important tool for analyzing disordered arrangement of atoms in crystals. In this study the oscillatory of diffuse scattering intensity of PbF$$_{2}$$ was observed both in wavelength-dispersive and angular-dispersive neutron scattering measurements, and we discuss the diffuse neutron scattering intensity by TOF measurement on powder sample of PbF$$_{2}$$ compared with those by angular-dispersive diffraction patterns. The diffuse scattering theory including the correlation effects among thermal displacements of atoms is effective for the treatment of diffuse background intensity obtained by TOF neutron experiment.

Journal Articles

The Ibaraki prefecture materials design diffractometer for J-PARC; Designing neutron guide

Harjo, S.; Kamiyama, Takashi*; Torii, Shuki; Ishigaki, Toru; Yonemura, Masao*

Physica B; Condensed Matter, 385-386(Part 2), p.1025 - 1028, 2006/11

 Times Cited Count:4 Percentile:23.8(Physics, Condensed Matter)

Ibaraki Prefecture Materials Design Diffractometer of J-PARC is a time-of-flight neutron powder diffractometer with the resolution as good as $$Delta d$$/$textit{d}$ = 0.16 % (almost constant value) for $$0.18<d($$$AA$)<5$$ (L1 of 26.5 m). Since this diffractometer has many detectors covering wide 2$$theta$$ range, measurements with wide $textit{Q}$ range, $$0.007<Q($$$AA$^{-1}$$$$)< 50$$, i.e., PDF analysis and small angle scattering can also be performed. Designing of neutron guide is therefore very important to enhance the performances mentioned above without sacrificing beam intensity. Non-parallel guides including elliptical ones have been compared with a linear-straight guide using the McStas simulation. The elliptical guide having the exit focal points away behind the sample position is available to increase the neutron flux at the sample but give a slight lowering of the instrumental resolution. This elliptical guide gives also Garland peaks at short wavelengths that may give large ambiguities in powder diffraction measurements. Therefore, the linear-straight guide is considered as the best choice for this instrument to keep a good resolution and also a relatively high flux.

Oral presentation

The Ibaraki prefecture materials design diffractometer for J-PARC

Ishigaki, Toru; Harjo, S.; Yonemura, Masao*; Kamiyama, Takashi*; Mori, Kazuhiro*; Mochiku, Takashi*; Aizawa, Kazuya; Arai, Masatoshi; Ebata, Kazuhiro*; Takano, Yoshiki*

no journal, , 

no abstracts in English

Oral presentation

Structure investigation on layered cathode materials of lithium-ion battery

Yonemura, Masao*; Kamiyama, Takashi*; Ishigaki, Toru; Mori, Kazuhiro*; Harjo, S.; Iwase, Kenji*; Takeuchi, Yoji*; Sasaki, Tsuyoshi*; Ukyo, Yoshio*

no journal, , 

The layered rock-salt structural materials, LiMO$$_{2}$$ (M=Ni, Co, etc.) are promising candidates as cathodes in rechargeable lithium-ion batteries. These materials are defective in their electrochemical properties because their structures and thermal propertiesare unstable during the lithium (de)intercalation process. However, the substituted Li(Ni,Co,Al)O$$_{2}$$ system shows the good electrochemical and thermal properties. The Mg doped system, Li(M,Mg)O$$_{2}$$, also shows good cycle stabilities. In this study, the effect of Mg doping into the Li(Ni,Co,Al,Mg)O$$_{2}$$ system was studied with Mg compositions between 0 $$<$$ Mg $$<$$ 0.1. In this presentation, the detailed structure will be discussed.

Oral presentation

Thermal expansion behavior of iron carbide Fe$$_{3}$$C

Harjo, S.; Shiota, Yoshinori*; Yonemura, Masao*; Tomota, Yo*; Kamiyama, Takashi*; Umemoto, Minoru*

no journal, , 

Iron Carbide Fe$$_{3}$$C (called "cementite") is an important phase for engineering steels. The amount and shape of cementite determine mechanical and thermal properties of the steels. Cementite is also suggested as the major phase in the inner core of the centre of the earth. However, since the cementite single-phase specimen was so difficult to prepare, its physical properties have not been examined well. Recently, the preparation of cementite bulky specimen has been performed by using plasma-sintering with mechanical milling. The lattice parameters of the prepared bulky pure cementite and Mn-alloyed cementite were measured at VEGA-KENS (Time-of-Flight neutron powder diffractometer) in a temperature range from room temperature to 673 K, to determine their thermal expansion coefficients. Results of the measurements will be presented.

Oral presentation

Ibaraki materials design diffractometer for J-PARC

Ishigaki, Toru; Hoshikawa, Akinori; Yonemura, Masao*; Kamiyama, Takashi*; Harjo, S.; Aizawa, Kazuya; Sakuma, Takashi*; Tomota, Yo*; Morii, Yukio; Arai, Masatoshi; et al.

no journal, , 

Ibaraki prefecture, the local goverment of the area for J-PARC site, was decided to build a versatile neutron diffractometer (IBARAKI Materials Design Diffractometer) to promote a industrial application for neutron beam in J-PARC. This diffractometer is planned to be a high throughput diffractometer so that materials engineers and scientists can use it like the chemical analytical instruments in their materials development process. It covers in d range 0.18 $$<$$ d (${AA}$) $$<$$ 5 with $$Delta $$ $$d/d$$ = 0.16% at high resolution bank, and covers 5 $$<$$ d (${AA}$) $$<$$ 800 with gradually changing resolution at three detector bank (90 degree, low angle and small angle). Typical measuring time to obtain a "Rietveld-quality" data is several minutes with the sample size of laboratory X-ray diffractometer. To promote industrial application, a utilization system for this diffractometer is required. We will establish a support system for both academic and industrial users who are willing to use neutron but have not been familiar with neutron diffraction. The construction of this instrument was already begun and will be compleated in the beggining of 2008, as one of day-one instruments for J-PARC.

Oral presentation

Object oriented data analysis environment for neutron scattering

Suzuki, Jiro*; Kajimoto, Ryoichi; Ohara, Takashi; Yonemura, Masao*; Aoyagi, Tetsuo; Manabe, Atsushi*; Nakatani, Takeshi; Otomo, Toshiya*; Kawabata, Setsuya*

no journal, , 

Manyo-Lib is a framework of software designed for data analysis for neutron scattering experiment. It is one of the fundamental software used in J-PARC/MLF. Manyo-Lib consists of class libraries of C++ and Python interfaces that wrap the class libraries. The purpose of Manyo-lib is to offer operators for analysis, data containers, distributed computing environment, common data formats necessary to analyzing experiment data generated by various scattering equipments and various research regions. We are going to use NeXus as our common file format.

Oral presentation

Present status for Ibaraki materials design diffractometer

Ishigaki, Toru; Hoshikawa, Akinori; Yonemura, Masao*; Kamiyama, Takashi*; Mori, Kazuhiro*; Mochiku, Takashi*; Aizawa, Kazuya; Arai, Masatoshi; Ebata, Kazuhiro*; Takano, Yoshiki*; et al.

no journal, , 

no abstracts in English

Oral presentation

IBARAKI materials design diffractometer; Versatile neutron diffractometer at J-PARC

Ishigaki, Toru; Hoshikawa, Akinori; Yonemura, Masao*; Kamiyama, Takashi*; Aizawa, Kazuya; Sakuma, Takashi*; Tomota, Yo*; Morii, Yukio; Arai, Masatoshi; Hayashi, Makoto*; et al.

no journal, , 

Ibaraki prefecture, the local government of the area for J-PARC site, was decided to build a versatile neutron diffractometer (IBARAKI Materials Design Diffractometer) to promote an industrial application for neutron beam in J-PARC. This diffractometer is planned to be a high throughput diffractometer so that materials engineers and scientists can use it like the chemical analytical instruments in their materials development process. It covers in d range 0.18 $$<$$ d (${AA}$) $$<$$ 5 with $$Delta$$ d/d = 0.16 % at high resolution bank, and covers $$<$$ d (${AA}$) $$<$$ 800 with gradually changing resolution at three detector bank (90 degree, low angle and small angle). Typical measuring time to obtain a "Rietveld-quality" data is several minutes with the sample size of laboratory X-ray diffractometer. To promote industrial application, a utilization system for this diffractometer is required. We will establish a support system for both academic and industrial users who are willing to use neutron but have not been familiar with neutron diffraction. The construction of this instrument was already beginning and will be completed in the beginning of 2008, as one of day-one instruments for J-PARC. The current status for this instrument also will be reported.

Oral presentation

Software development for neutron experimental instruments at MLF, J-PARC

Nakatani, Takeshi; Inamura, Yasuhiro; Ito, Takayoshi; Kajimoto, Ryoichi; Aoyagi, Tetsuo; Ohara, Takashi; Otomo, Toshiya*; Yasu, Yoshiji*; Suzuki, Jiro*; Morishima, Takahiro*; et al.

no journal, , 

We have started the commissioning of the neutron scattering experiment instruments since May 2008 in MLF, J-PARC. Simultaneously, we have started the commissioning of the data acquisition and analysis software. Experimental users operate this software through the software framework which we have developed. The software framework was developed based on Python which is an object oriented script language. The system implemented with the software framework can seamlessly measure, analyze and visualize with some modules which are experimental control and data analysis. In this presentation, we report the process of the construction and the current status of the software.

Oral presentation

Software for the engineering materials diffractometer (TAKUMI) at MLF, J-PARC

Ito, Takayoshi; Harjo, S.; Arima, Hiroshi; Abe, Jun; Moriai, Atsushi; Aizawa, Kazuya; Arai, Masatoshi; Nakatani, Takeshi; Inamura, Yasuhiro; Hosoya, Takaaki*; et al.

no journal, , 

no abstracts in English

Oral presentation

Cross-sectional hydrogen content and mass density profiles of DLC film by neutron and X-ray reflectivity

Ozeki, Kazuhide*; Yonemura, Masao*; Masuzawa, Toru*; Saito, Hidetoshi*; Ogoe, Yasuharu*; Hirakuri, Kenji*; Takeda, Masayasu

no journal, , 

Hydrogen content in the DLC film is very important factor because it greatly influences on its mechanical properties and microstructure such as hardness, wear resistance, surface roughness, and sp3/sp2 ratio. In the present study, we prepared the DLC film using plasma CVD technique varying H$$_{2}$$/CH$$_{4}$$ ratio from 0 to 9. Cross-sectional hydrogen content and mass density profiles of the films were defined by neutron and X-ray reflectivity measurements, and the results were compared with that from ERDA analysis. And O/C atomic ratio of the oxide layer of the film surface was also analyzed using XPS. From the neutron and X-ray reflectivity analysis, hydrogen content and mass density in the DLC film increased with film depth from the surface, and average hydrogen content showed more than 30 % in all films. By combining with XPS results, it is clarified that hydrogen content in the surface layer was lower than that in bulk layer.

Oral presentation

In situ crystallographic observation of dynamic ferrite transformation evolution during hot deformation of low alloy steels

Xu, P. G.; Tomota, Yo*; Koo, M.*; Yonemura, Masao*; Suzuki, Tetsuya*; Paradowska, A.*; Zhang, S. Y.*; Adachi, Yoshitaka*

no journal, , 

Deformation induced ferrite transformation related to microstructure refinement has attracted wide attention. However, the in situ crystallographic evolution studies have not been carried out. In this paper, the deformation induced ferrite transformation at two different strain rates was carried out to compare that during isothermal holding without deformation and the effects of hot deformation and strain rate on the dynamic transformation evolution was investigated. The neutron diffraction experiments confirmed that the deformation induced ferrite transformations could appear not only in the austenite region, but also in the austenite-ferrite dual phase region. It was found that the low temperature deformation was more effective than the high temperature to promote the ferrite transformation until a critical strain, and then the accelerating effect was weakened due to the increment of austenite carbon concentration and the appearance of ferrite dynamic recrystallization.

Oral presentation

Current status and future plan of the software framework in MLF computing environment

Nakatani, Takeshi; Inamura, Yasuhiro; Ito, Takayoshi; Kajimoto, Ryoichi; Harjo, S.; Arai, Masatoshi; Ohara, Takashi; Nakagawa, Hiroshi; Aoyagi, Tetsuo; Otomo, Toshiya*; et al.

no journal, , 

We have developed the software framework in MLF computing environment from 2006 to 2008. The software framework is the fundamental software for neutron and muon experimental instruments in J-PARC/MLF. Currently, the software framework is installed at 4D Space Access Neutron Spectrometer (BL01), IBARAKI Biological Crystal Diffractometer (BL03), Cold-Neutron Disk-Chopper Spectrometer (BL14), Engineering Materials Diffractometer (BL19) and High Intensity Total Diffractometer (BL21). The features of experimental control, analysis, visualization and authorization are already implemented in the software framework. In this year, we will start the development to introduce the feature of database. We will present the current status and future plan of the software framework.

24 (Records 1-20 displayed on this page)