Mode distribution analysis for superionic melt of CuI by coherent quasielastic neutron scattering

Kawakita, Yukinobu; Kikuchi, Tatsuya*; Tahara, Shuta*; Nakamura, Mitsutaka; Inamura, Yasuhiro; Maruyama, Kenji*; Yamauchi, Yasuhiro*; Kawamura, Seiko; Nakajima, Kenji

JPS Conference Proceedings (Internet), 33, p.011071_1 - 011071_6, 2021/03

BB2019-1144.pdf:0.7MB

https://doi.org/10.7566/JPSCP.33.011071

CuI is a well-known superionic conductor in a high temperature solid phase where the mobile cations migrate between interstitial sites in the f.c.c. sublattice formed by iodine ions. Even in the molten state, it shows several features suggesting collective or cooperative ionic motion. MD results show that Cu diffuses much faster than I. The Cu-Cu partial structure factor have a FSDP which indicates a medium-range ordering of Cu ions. Moreover the Cu-Cu partial pair distribution deeply penetrates into the nearest neighboring Cu-I shell. To reveal origin such anomalous behaviors of molten CuI, we performed quaiselastic neutron scattering (QENS) by the disk-chopper spectrometer AMATERAS at MLF, J-PARC. To interpret the total dynamic structure factor obtained from coherent QENS, the mode distribution analysis was applied. It is found that the motion of iodine is a kind of fluctuating within an almost local area while Cu ions diffuse much faster than iodine ions.

Cryogenic sample environments shared at the MLF, J-PARC

Kawamura, Seiko; Takahashi, Ryuta*; Ishikado, Motoyuki*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ouchi, Keiichi*; Kira, Hiroshi*; Kambara, Wataru*; Aoyama, Kazuhiro*; Sakaguchi, Yoshifumi*; et al.

Journal of Neutron Research, 21(1-2), p.17 - 22, 2019/05

https://doi.org/10.3233/JNR-190106

The Cryogenics and Magnets group in the Sample Environment team is responsible for operation of cryostats and magnets for user's experiments at the MLF in J-PARC. We have introduced a top-loading He cryostat, a bottom-loading He cryostat, a dilution refrigerator insert and a superconducting magnet. The frequency of use of them dramatically becomes higher in these two years, as the beam power and the number of proposal increase. To respond such situation, we have made efforts to enhance performance of these equipment as follows. The He cryostat originally involves an operation software for automatic initial cooling down to the base temperature and automatic re-charge of He. Recently we made an additional program for automatic temperature control with only the sorb heater. Last year, a new outer vacuum chamber of the magnet with an oscillating radial collimator (ORC) was fabricated. The data quality was drastically improved by introducing this ORC so that the magnet can be used even for the inelastic neutron scattering experiments.

Neutron inelastic scattering study of the -electron states in NdPdAl

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

https://doi.org/10.7566/JPSJ.87.084708

Inelastic neutron scattering experiments were carried out in order to study the -electron states of NdPdAlThe CEF levels at 0K, 35.4K, 88.3K, 101.5K, and 198.8K were clarified from the excitation spectra. The ground state contains the orbital with as a main component due to a large negative BK, 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 CePdAl and PrPdAl. Indicates that a localized character is important even in actinide-based iso-structural compounds as actually observed in UPdAl and also NpPdAl, in which the valence crossover plays important role for the heavy fermion superconductivity.

Sample environment at the J-PARC MLF

Kawamura, Seiko; Oku, Takayuki; Watanabe, Masao; Takahashi, Ryuta; Munakata, Koji*; Takata, Shinichi; Sakaguchi, Yoshifumi*; Ishikado, Motoyuki*; Ouchi, Keiichi*; Hattori, Takanori; et al.

Journal of Neutron Research, 19(1-2), p.15 - 22, 2017/11

https://doi.org/10.3233/JNR-170046

Sample environment (SE) team at the Materials and Life Science Experimental Facility (MLF) in J-PARC has worked on development and operation of SE equipment and devices. All the members belong to one sub-team at least, such as Cryogenic and magnet, High temperature, High pressure, Soft matter and special environment including Pulse magnet, Hydrogen environment, Light irradiation and He spin filter. Cryostats, a magnet, furnaces, a VX-6-type Paris-Edinburgh press and a prototype of a Spin-Exchange Optical Pumping (SEOP) based He spin filter for polarized neutron beam experiments are in operation. Furthermore, a prototype of compact power supply for a pulsed magnet system is currently developed. In the J-PARC Research Building, several pieces of equipment for softmatter research such as a rheometer and a gas and vapor adsorption measurement instrument have been prepared.

Sample environment at the MLF

Aso, Tomokazu; Yamauchi, Yasuhiro; Kawamura, Seiko

Hamon, 25(4), p.283 - 287, 2015/11

Interesting phenomena detected by the continuous observation of strain and in-situ stress measurements in the vicinity of the active Mozumi-Sukenobe fault

Ishii, Hiroshi*; Yamauchi, Tsuneo*; Asai, Yasuhiro*; Matsumoto, Shigeo*; Mukai, Atsushi*

Geodynamics of Atotsugawa Fault System, p.157 - 162, 2007/00

Investigation of the behavior of stress and strain in the vicinity of active faults provides valuable data. We have performed continuous strain observation and stress measurements in the active Mozumi-Sukenobe Fault. Two strain meters were installed on both sides of the crushed zones. Characteristic strain variations on both sides indicate right lateral movements that are almost identical to the movements of the fault. The stress measurements also indicate the same pattern as the fault movements, although the values are smaller than usual. The reason proposed is that the crushed zone of the fault can not accumulate stress. The behavior of strain variation suggests that fault movements are caused by the actions of tectonic stress but that the accumulation of this stress is small in the vicinity of the fault stress.

Real-time monitoring of oxidation on the Ti(0001) surface by synchrotron radiation photoelectron spectroscopy and RHEED-AES

Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden; Yamauchi, Yasuhiro*; Mizuno, Yoshiyuki*; Tonda, Hideki*; Homma, Teiichi*

Applied Surface Science, 216(1-4), p.395 - 401, 2003/06

https://doi.org/10.1016/S0169-4332(03)00453-7

Real-time in-situ observation using photoelectron spectroscopy for elementary processes of Ti(0001) oxidation by O molecules has been performed at the surface reaction analysis apparatus installed at the BL23SU in the SPring-8. And the real-time observation has been also performed by RHEED-AES methods at Tohoku University. The partial pressure region of oxygen was from 2x10 Torr to 8x10 Torr. The surface temperature was 473 K and 673 K. The variation from clean Ti surface toward TiO was comfirmed by observation of Ti-2p and O-1s photoelectron spectra. Reflected electron intensity and O-KLL Auger electron intensity oscillated in the RHEED-AES measurements. These facts revealed that the surface morphological change of the oxidized Ti(0001) surface was associated not only with a disappearance of the surface metallic layer but also with a change of the oxidation state.

Current status of sample environment in MLF, J-PARC

Kawamura, Seiko; Yokoo, Tetsuya*; Kambara, Wataru; Inamura, Yasuhiro; Nakatani, Takeshi; Torii, Shuki*; Kajimoto, Ryoichi; Nakajima, Kenji; Kaneko, Koji; Kawakita, Yukinobu; et al.

no journal, , 

Materials and Life Science Experimental Facility at J-PARC started the user program in December 2008. Various neutron experiments are currently performed there in wide range of scientific researches and industrial applications. Standardization of sample environment (SE) equipments is one of the most important things at the beginning stage. Especially in our country, it often happens that each instrument carries and operates SE devices independently. This situation results in an excess of the cost and incompatibility among the instruments unless we have any guidelines. Thus the SE team has discussed the SE-protocol, in which flange size, thermometers, controllers etc. are standardized. This should bring about saving the cost and manpower and increasing compatibility. The SE team is now discussing user support system in SE, preparation of the SE area, and so on. The technical staff members started working on practical things such as cooling test of cryostats.

Current status and future plan of sample environment in MLF, J-PARC

Kawamura, Seiko; Yokoo, Tetsuya*; Kambara, Wataru; Munakata, Koji*; Kajimoto, Ryoichi*; Nakatani, Takeshi; Kaneko, Koji; Kawakita, Yukinobu; Takata, Shinichi; Nakajima, Kenji; et al.

no journal, , 

In large user facilities such as neutron experimental facilities, sample environment (SE) is one of the most important factors to yield high-quality output. In the Materials and Life Science Experimental Facility (MLF) in J-PARC, various neutron experiments have been performed in wide range of scientific researches and industrial applications, and the number and variety of proposals will further increase after resuming operation of J-PARC. At the beginning stage, the SE team in MLF has discussed SE standardization, to save the cost and manpower, to make compatibility among instruments, and to increase the experimental efficiency by sharing the SE devices and techniques for operation. Recently we started preparation of "SE area" in the experimental hall, where we can do maintenance of equipments, pre-cooling of cryostats and so on. The SE team is now discussing future plan including user support system.

The Construction report of the Si crystal analyzer near backscattering spectrometer, 6

Shibata, Kaoru*; Takahashi, Nobuaki; Kawakita, Yukinobu; Kamazawa, Kazuya*; Yamada, Takeshi*; Ueno, Hiroki; Shimakura, Hironori; Nakajima, Kenji; Kambara, Wataru; Inamura, Yasuhiro; et al.

no journal, , 

no abstracts in English