Spiral spin cluster in the hyperkagome antiferromagnet MnRhSi

Shamoto, Shinichi; Yamauchi, Hiroki; Iida, Kazuki*; Ikeuchi, Kazuhiko*; Hall, A. E.*; Chen, Y.-S.*; Lee, M. K.*; Balakrishnan, G.*; Chang, L.-J.*

Communications Physics (Internet), 6, p.248_1 - 248_6, 2023/09

https://doi.org/10.1038/s42005-023-01363-1

We show that the local spin correlation order has a spiral structure by neutron scattering measurement of a MnRhSi single crystal. The possible origins of the magnetic cluster formation are discussed in terms of the Lifshitz invariant and the Griffiths phase, and compared with the room-temperature skyrmion phase of CoZnMn and non-Fermi liquid behavior of -Mn.

Numerical interpretation of hydrogen thermal desorption spectra for iron with hydrogen-enhanced strain-induced vacancies

Ebihara, Kenichi; Sugiyama, Yuri*; Matsumoto, Ryosuke*; Takai, Kenichi*; Suzudo, Tomoaki

Metallurgical and Materials Transactions A, 52(1), p.257 - 269, 2021/01

https://doi.org/10.1007/s11661-020-06075-7

We simulated the thermal desorption spectra of a small-size iron specimen to which was applied during charging with hydrogen atoms using a model incorporating the behavior of vacancies and vacancy clusters. The model considered up to vacancy clusters , which is composed of nine vacancies and employed the parameters based on atomistic calculations, including the H trapping energy of vacancies and vacancy clusters that we estimated using the molecular static calculation. As a result, we revealed that the model could, on the whole, reproduced the experimental spectra except two characteristic differences, and also the dependence of the spectra on the aging temperature. By examining the cause of the differences, the possibilities that the diffusion of clusters of and is slower than the model and that vacancy clusters are generated by applying strain and H charging concurrently were indicated.

Time-controlled synthesis of the 3D coordination polymer U(1,2,3-Hbtc) followed by the formation of molecular poly-oxo cluster {} containing hemimellitate uranium(IV)

Dufaye, M.*; Martin, N. P.*; Duval, S.*; Volkringer, C.*; Ikeda, Atsushi; Loiseau, T.*

RSC Advances (Internet), 9(40), p.22795 - 22804, 2019/07

AA2019-0270.pdf:1.14MB

https://doi.org/10.1039/C9RA03707A

Two coordination compounds bearing tetravalent uranium (UIV)) were synthesized in the presence of tritopic hemimellitic acid in acetonitrile with a controlled amount of water (HO/U 8) and structurally characterized. The slow hydrolysis reaction together with the partial decomposition of the starting organic reactants into oxalate and acetate molecules induces the generation of such a large poly-oxo cluster with fourteen uranium centers. Structural comparisons with other closely related uranium-containing clusters, such as the {}O] with three dinuclear sub-units {}, were performed.

Present status of JAEA-Tokai tandem accelerator

Kabumoto, Hiroshi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Matsuda, Makoto; Nakanoya, Takamitsu; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1404 - 1408, 2017/12

The JAEA-Tokai tandem accelerator was operated over a total of 110 days, and delivered 22 different ions to the experiments in the research fields of nuclear physics, nuclear chemistry, atomic physics, solid state physics and radiation effects in material in FY2016. The damaged acceleration tubes by discharge were replaced with the spare tube at the regular maintenance period in March 2016, and the maximum accelerating voltage recovered to the 17 MV. However, an accident of vacuum breaking of all acceleration tubes was occurred in December, and accelerating voltage fell down to under 12 MV. Now, we are doing the maintenance to recover the performance of acceleration voltage. This paper describes the operational status of the accelerators and the major technical developments of our facility.

Fine dispersion of Pt subnanoclusters and Pt single atoms over porous carbon supports and their structural analyses with X-ray absorption spectroscopy

Itoi, Hiroyuki*; Nishihara, Hirotomo*; Kobayashi, Shunsuke*; Ittisanronnachai, S.*; Ishii, Takafumi*; Berenguer, R.*; Ito, Masashi*; Matsumura, Daiju; Kyotani, Takashi*

Journal of Physical Chemistry C, 121(14), p.7892 - 7902, 2017/04

https://doi.org/10.1021/acs.jpcc.7b00422

Atomic structure and physical properties of fused porphyrin nanoclusters

Avramov, P. V.*; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu*; Entani, Shiro; Matsumoto, Yoshihiro*; Eleseeva, N. S.*; Pomogaev, V. A.*; Naramoto, Hiroshi*

Journal of Porphyrins and Phthalocyanines, 18(7), p.552 - 568, 2014/07

https://doi.org/10.1142/S1088424614500291

Coupled electron and atomic kinetics through the solution of the Boltzmann equation for generating time-dependent X-ray spectra

Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Kilcrease, D. P.*; Dodd, E. S.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; et al.

Journal of Quantitative Spectroscopy & Radiative Transfer, 99(1-3), p.584 - 594, 2006/05

https://doi.org/10.1016/j.jqsrt.2005.05.047

In this work, we present a model that solves self-consistently the electron and atomic kinetics to characterize highly non-equilibrium plasmas, in particular for those systems where both the electron distribution function is far from Maxwellian and the evolution of the ion level populations are dominated by time dependent atomic kinetics. In this model, level populations are obtained from a detailed collisional-radiative model where collision rates are computed from a time varying electron distribution function obtained from the solution of the zero-dimensional Boltzmann equation. The Boltzmann collision term includes the effects of electron-electron collisions, electron collisional ionization, excitation and de-excitation. An application for He spectra from a short pulse laser irradiated argon cluster target will be shown to illustrate the results of our model.

MeV cluster ions from TIARA 3MV tandem accelerator

Saito, Yuichi; Chiba, Atsuya; Narumi, Kazumasa

Dai-18-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.47 - 49, 2005/11

no abstracts in English

Size of small Si and Ge clusters on Si(111) and Ge(111) surfaces

Asaoka, Hidehito; Cherepanov, V.*; Voigtlnder, B.*

Surface Science, 588(1-3), p.19 - 25, 2005/08

https://doi.org/10.1016/j.susc.2005.05.022

We determined the average size of small Si and Ge clusters conned to one half of a (77) or (55) unit cell of a Si or Ge(111) surface. The size of Si and Ge clusters conned to a Si(111)-(77) half unit cell was determined to be 8.31 atoms and 7.51 atoms, respectively for a growth temperature of 400 K. This is the same value within the error and shows, that the material of the clusters is less important for the cluster size. On the Ge surface it was found that the reconstruction unit cell is important for the cluster size. On the (55) reconstructed Ge(111) surface the Si clusters have a smaller size of 4.71 atoms compared to 8.21 atoms for Si clusters on the Ge(111)-(77) surface.

Measurement of ' X-ray transitions from 1 m Kr clusters irradiated by high-intensity femtosecond laser pulses

Hansen, S. B.*; Fournier, K. B.*; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; Skobelev, I. Y.*; Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; et al.

Physical Review E, 71(1), p.016408_1 - 016408_9, 2005/01

https://doi.org/10.1103/PhysRevE.71.016408

X-ray line emission from ' transitions in Ne-like Kr and nearby ions has been observed from 1 m Kr clusters irradiated by fs-scale laser pulses at the JAERI facility in Kyoto, Japan. The dependence of X-ray spectral features and intensity on the incident laser intensity is rather weak, indicating that the 1-2 ps cluster lifetimes limit the number of ions beyond Ne-like Kr that can be produced by collisional ionization. A collisional-radiative model based on the relativistic multiconfigured FAC code has been constructed and used to determine that the cluster plasma has electron densities near 10 cm, temperature of a few hundred eV and hot electron fraction of a few percent.