研究者詳細 - 武藤　俊介

論文 - 武藤　俊介

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Magnetic measurements with atomic plane resolution 査読有り

J. Rusz, S. Muto, J. Spiegelberg, R. Adam, K. Tatsumi, D. E. Burgler, P. M. Oppeneer, C. M. Schneider

Nature Communications 7 巻頁： 12672 2016年8月

Quantitative characterisation of nanoscale polycrystalline magnets with electron magnetic circular dichroism 査読有り

Shunsuke Muto, Ján Rusz, Kazuyoshi Tatsumi, Roman Adam, Shigeo Arai, Vancho Kocevski, Peter M. Oppeneer, Daniel E. Bürgler & Claus M. Schneider

Nature Communications 5 巻 ( 3138 ) 頁： 1-7 2014年1月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

Electron magnetic circular dichroism (EMCD) allows the quantitative, element-selective determination of spin and orbital magnetic moments, similar to its well-established X-ray counterpart, X-ray magnetic circular dichroism (XMCD). As an advantage over XMCD, EMCD measurements are made using transmission electron microscopes, which are routinely operated at sub-nanometre resolution, thereby potentially allowing nanometre magnetic characterization. However, because of the low intensity of the EMCD signal, it has not yet
been possible to obtain quantitative information from EMCD signals at the nanoscale. Here we demonstrate a new approach to EMCD measurements that considerably enhances the outreach of the technique. The statistical analysis introduced here yields robust quantitative EMCD signals. Moreover, we demonstrate that quantitative magnetic information can be
routinely obtained using electron beams of only a few nanometres in diameter without imposing any restriction regarding the crystalline order of the specimen.

DOI： DOI: 10.1038/ncomms4138

Spin crossover and iron-rich silicate melt in the Earth's deeep mantle 査読有り

R.Nomura, H.Ozawa, S.Tateno, K.Hirose, J.Hernlund, S.Muto, H.Ishii and N.Hiraoka

NATURE 473 巻頁： 199-202 2011年5月

*Novel valence state of cerium in Ce2Zr2O7.5 elucidated by electron energy-loss spectroscopy under electron channeling conditions 査読有り

S. Arai, S. Muto, T. Sasaki, K. Tatsumi, Y. Ukyo, K. Kuroda and H. Saka

Solid State Communications 135 巻頁： 664-667 2005年

記述言語：英語掲載種別：研究論文（学術雑誌）

In the present study, we show, by electron energy loss spectroscopy (EELS) measurements under electron channeling conditions, the existence of a novel valence state for the cerium atoms in Ce2Zr2O7.5, where the valence state is split into two states, with the ions exhibiting a trivalent character (Ce3+) when facing oxygen planes with oxygen vacancies, and a tetravalent character (Ce4+) when facing oxygen planes with no oxygen vacancies. This result should prompt reconsideration of the conventional concept of the valence fluctuation in rare earth compounds.

*Local electronic structure analysis by site-selective ELNES using electron channeling and first-principles calculations 招待有り査読有り

K. Tatsumi and S. Muto

J. Phys.: Condens. Matter 21 巻頁： 104213 (14 pages) 2009年

Site-specific electronic configurations of Fe 3d states by energy loss by channeled electrons 査読有り

K. Tatsumi, S. Muto, I. Nishida and J. Rusz

Applied Physics Letters 96 巻頁： 201911 (3 pages) 2010年4月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

Site-specific configurations of Fe 3d electrons in a spinel ferrite were investigated by electron energy loss spectroscopy (EELS) under electron channeling conditions. Site-specific spectra were extracted by applying a multivariate curve resolution (MCR) technique to the data set. An electronic difference in the Fe sites caused by ligand field splitting of trivalent Fe was probed. This demonstrated the promise of site-specific valence and spin state analysis in spintronics applications of spinel ferrites.

*Spectral restoration and energy resolution improvement of electron energy-loss spectra by Pixon reconstruction: I. Principle and test examples 査読有り

S. Muto, R. C. Puetter and K. Tatsumi

Journal of Electron Microscopy 55 巻頁： 215-223 2006年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

We applied Pixon deconvolution as introduced in Part I to several practical, examples of low signal-to-noise ratio (SNR), electron energy-loss spectra with a goal toward restoring their fine spectral features and/or improving the energy resolution. We demonstrate that by directly fitting the two-dimensional spectral data recorded on the CCD; the method enables us to reveal fine spectral structures. Consequently, Pixon reconstruction extends the ability to probe electronic states in very spatially localized areas, a capability currently unique to our method.

Mapping of heterogeneous chemical states of lithium in a LiNiO2-based active material by electron energy-loss spectroscopy 査読有り

S. Muto, K. Tatsumi, T. Sasaki, H. Kondo, T. Ohsuna, K. Horibuchi and Y. Takeuchi

Electrochemical Solid-State Letters 13 巻 ( 8 ) 頁： A115-117 2010年5月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

It is difficult to analyze the local concentrations and chemical states of lithium in lithium-ion secondary battery electrodes by microanalysis techniques based on TEM because the core excitation spectra of transition metals invariably overlap with the absorption/emission spectra of Li-K. We propose a promising analysis method that enables the spatial distribution of lithium with different chemical states from the original phase in a LiNiO2-based positive electrode to be visualized. It employs a suite of spectrum imaging techniques including scanning transmission electron microscopy, electron energy-loss spectroscopy, and multivariate curve resolution. This method is successfully applied to a cross-sectioned positive electrode.

Detection of hydrogen at localized regions by unoccupied electronic states in iron carbides: towards high spatial resolution mapping of hydrogen distributions 査読有り

K. Tatsumi, S. Muto and T. Yoshida

Journal of Applied Physics 101 巻頁： 023523-1-7 2007年

記述言語：英語掲載種別：研究論文（学術雑誌）

In the present study, we examined the effects of hydrogen on electron energy-loss and x-ray absorption spectra of the iron carbides. The experimentally obtained spectral changes were interpreted on the basis of first principles
calculations for a model structure of the Fe–C–H system. Finally, we demonstrate high spatial resolution imaging of hydrogen distributions in iron-carbon systems by an energy-filtering transmission electron microscopy technique, utilizing the present spectral changes associated with
hydrogen incorporation.

電子エネルギー損失スペクトル微細構造解析の軽元素分析への応用招待有り査読有り

武藤　俊介

顕微鏡 41 巻 ( 1 ) 頁： 26-31 2006年3月

Local atomic and electronic structures around Mg and Al dopants in LiNiO2 electrodes studied by XANES and ELNES and first-principles calculations 査読有り

K. Tatsumi, Y. Sasano, S. Muto, T. Yoshida, T. Sasaki, K. Horibuchi, Y. Takeuchi and Y. Ukyo

Physical Review B 78 巻頁： 045108(1-8) 2008年7月

記述言語：英語掲載種別：研究論文（学術雑誌）

We investigated the local atomic and electronic structures around the dopants Mg and Al in a LiNiO2-based cathode material by the combination analysis of their K shell electron energy loss near edge structures (ELNES) and x-ray absorption near edge structures (XANES), and first-principles calculations. The occupation sites of the dopants in initial and cycled samples were examined. On the basis of the atomic structures and chemical bonding states of the models whose theoretical spectra were most consistent with the experimental spectra, we discussed the effects of Al and Mg on Li diffusion and their roles in suppressing the degradation of battery properties.

Hydrogen trapping state associated with the low temperature thermal desorption spectroscopy peak in hydrogenated nanostructured graphite 査読有り

Y. Miyabe, T. Yoshida, S. Muto, T. Kiyobayashi and H. Wasada

Journal of Applied Physics 104 巻頁： 044311 2008年4月

Quantitative determination of site occupancy of multi-rare-earth elements doped into Ca2SnO4 phosphor by electron channeling microanalysis 査読有り

Y. Fujimichi, S. Muto, K. Tatsumi, T. Kawano and H. Yamane

journal of Solid State Chemistry 183 巻頁： 2127-2132 2010年8月

Capacity fading mechanism of LiNiO2-based lithium ion batteries: II. Diagnostic analysis by electron microscopy and spectroscopy 査読有り

S. Muto, Y. Sasano, K. Tatsumi, T. Sasaki, K. Horibuchi, Y. Takeuchi and Y. Ukyo

J. Electrochem. Soc. 156 巻頁： A371-A377 2009年4月

Grazing-incidence electron microscopy of surface blisters in single- and polycrystalline tungsten formed by H+, D+ and He+ irradiation 査読有り

N. Enomoto, S. Muto, T. Tanabe, J. W. Davis and A. A. Haasz

J. Nucl. Mater. 385 巻頁： 606-614 2009年

A study on the relationship of magnetic moments orientation in L1₀ FePt network nanostructured film by electron energy-loss magnetic chiral dichroism using semi-core excitation spectra 査読有り国際共著

H. Makino, J. Rusz, J. Wang, D. Turenne, M. Ohtsuka, Y. K. Takahashi, H. A. Dürr, S. Muto

Journal of Magnetism and Magnetic Materials 558 巻頁： 169522 2022年9月

Anode Properties of NaTi2(PO4)(3) Prepared by Adding Excess Na2CO3 for Aqueous Sodium-Ion Batteries

Kitajou Ayuko, Yamashita Maho, Kobayashi Wataru, Okada Masaki, Nanami Takuma, Muto Shunsuke

ACS APPLIED ENERGY MATERIALS 5 巻 ( 8 ) 頁： 9587 - 9594 2022年8月

Automating ALCHEMI at the nano-scale using software compatible with PC-controlled transmission electron microscopy

Ishizuka Akimitsu, Ohtsuka Masahiro, Muto Shunsuke

JOURNAL OF APPLIED CRYSTALLOGRAPHY 55 巻頁： 551 - 557 2022年6月

Binary dopant segregation enables hematite-based heterostructures for highly efficient solar H2O2 synthesis

Zhang Zhujun, Tsuchimochi Takashi, Ina Toshiaki, Kumabe Yoshitaka, Muto Shunsuke, Ohara Koji, Yamada Hiroki, Ten-no Seiichiro L., Tachikawa Takashi

NATURE COMMUNICATIONS 13 巻 ( 1 ) 2022年3月

STEM-EELS Spectrum Imaging of an Aerosol-Deposited NASICON-Type LATP Solid Electrolyte and LCO Cathode Interface

Muto Shunsuke, Yamamoto Yuta, Sakakura Miyuki, Tian Hong-Kang, Tateyama Yoshitaka, Iriyama Yasutoshi

ACS APPLIED ENERGY MATERIALS 5 巻 ( 1 ) 頁： 98 - 107 2022年1月

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