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1. Transverse thermoelectric conversion in the mixed-dimensional semimetal WSi$_2$

Author

Ohsumi, Shoya, Sato, Yoshiki J., and Okazaki, Ryuji

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons, Physics - Applied Physics
Abstract

Materials with axis-dependent conduction polarity are known as $p\times n$-type or goniopolar conductors that can be used for transverse thermoelectric devices, allowing the longitudinal thermal current to be converted into the transverse electrical current. Here, we performed experimental and computational studies on the transport properties of WSi$_2$ single crystals, in which such axis-dependent conduction polarity of the thermopower and the Hall coefficient have recently been reported, and demonstrated the transverse thermoelectric effect by applying the temperature gradient in a 45$^{\circ}$ rotated direction from the crystallographic axis. We have observed strongly sample-dependent transport properties, which have also been observed in previous studies, and together with first-principles calculations we show that such sample-dependent transport properties originate from the band-dependent scattering rates of carriers. The calculated band-resolved Peltier conductivity shows that the mixed-dimensional electronic structure consisting of a quasi-one-dimensional electron Fermi surface and a quasi-two-dimensional hole surface is a key property for the axis-dependent conduction polarity. The directly obtained transverse thermoelectric figure of merit is comparable to that of the anomalous Nernst materials, implying that the present material is a potential candidate for transverse thermoelectric conversion., Comment: 10 pages, 8 figures. Accepted for publication in PRX Energy

Published
2024
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2. The Ni isotopic composition of Ryugu reveals a common accretion region for carbonaceous chondrites

Author

Spitzer, Fridolin, Kleine, Thorsten, Burkhardt, Christoph, Hopp, Timo, Yokoyama, Tetsuya, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel M. O'D., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, Morita, Mayu, Moynier, Fréderic, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

The isotopic compositions of samples returned from Cb-type asteroid Ryugu and Ivuna-type (CI) chondrites are distinct from other carbonaceous chondrites, which has led to the suggestion that Ryugu and CI chondrites formed in a different region of the accretion disk, possibly around the orbits of Uranus and Neptune. We show that, like for Fe, Ryugu and CI chondrites also have indistinguishable Ni isotope anomalies, which differ from those of other carbonaceous chondrites. We propose that this unique Fe and Ni isotopic composition reflects different accretion efficiencies of small FeNi metal grains among the carbonaceous chondrite parent bodies. The CI chondrites incorporated these grains more efficiently, possibly because they formed at the end of the disk's lifetime, when planetesimal formation was also triggered by photoevaporation of the disk. Isotopic variations among carbonaceous chondrites may thus reflect fractionation of distinct dust components from a common reservoir, implying CI chondrites and Ryugu may have formed in the same region of the accretion disk as other carbonaceous chondrites., Comment: Published open access in Science Advances

Published
2024
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3. Thermoelectric transport properties of the quasi-one-dimensional dimer-Mott insulator $\beta'$-(BEDT-TTF)$_2$ICl$_2$

Author

Eguchi, Kyohei, Ito, Takeru, Sato, Yoshiki J., Okazaki, Ryuji, and Taniguchi, Hiromi

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter, Physics - Chemical Physics
Abstract

Low-dimensional materials, in which the electronic and transport properties are drastically modified in comparison to those of three-dimensional bulk materials, yield a key class of thermoelectric materials with high conversion efficiency. Among such materials, the organic compounds may serve peculiar properties owing to their unique molecular-based low-dimensional structures with highly anisotropic molecular orbitals. Here we present the thermoelectric transport properties of the quasi-one-dimensional dimer-Mott insulator $\beta'$-(BEDT-TTF)$_2$ICl$_2$, where BEDT-TTF stands for bis(ethylenedithio)-tetrathiafulvalene. We find that the thermopower exhibits typical activation-type temperature variation expected for insulators but its absolute value is anomalously large compared to the expected value from the activation-type temperature dependence of the electrical resistivity. Successively, the Jonker-plot analysis, in which the thermopower is usually scaled by the logarithm of the resistivity, shows an unusual relation among such transport quantities. We discuss a role of the low dimensionality for the enhanced thermopower along with recent observations of such a large thermopower in several low-dimensional materials., Comment: 7 pages, 5 figures. Accepted for publication in Phys. Rev. Materials

Published
2024
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4. Negatively enhanced thermopower near a Van Hove singularity in electron-doped Sr$_2$RuO$_4$

Author

Nishinakayama, Rei, Sato, Yoshiki J., Yamanaka, Takayoshi, Maeno, Yoshiteru, Yaguchi, Hiroshi, Kikugawa, Naoki, and Okazaki, Ryuji

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science, Condensed Matter - Superconductivity
Abstract

The layered perovskite Sr$_2$RuO$_4$ serves as a model material of the two-dimensional (2D) Fermi liquid but also exhibits various emergent phenomena including the non-Fermi-liquid (NFL) behavior under external perturbations such as uniaxial pressure and chemical substitutions. Here we present the thermoelectric transport of electron-doped system Sr$_{2-y}$La$_{y}$RuO$_4$, in which a filling-induced Lifshitz transition occurs at the Van Hove singularity (VHS) point of $y\approx 0.2$. We find that the sign of the low-temperature thermopower becomes negative only near the VHS point, where the NFL behavior has been observed in the earlier work. This observation is incompatible with either a numerical calculation within a constant relaxation-time approximation or a toy-model calculation for the 2D Lifshitz transition adopting an elastic carrier scattering. As a promising origin of the observed negatively enhanced thermopower, we propose a skewed NFL state, in which an inelastic scattering with a considerable odd-frequency term plays a crucial role to negatively enhance the thermopower., Comment: 10 pages, 7 figures, to be published in Phys. Rev. Research

Published
2024
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5. Microscale Hydrogen, Carbon, and Nitrogen Isotopic Diversity of Organic Matter in Asteroid Ryugu

Author

Nittler, Larry R, Barosch, Jens, Burgess, Katherine, Stroud, Rhonda M, Wang, Jianhua, Yabuta, Hikaru, Enokido, Yuma, Matsumoto, Megumi, Nakamura, Tomoki, Kebukawa, Yoko, Yamashita, Shohei, Takahashi, Yoshio, Bejach, Laure, Bonal, Lydie, Cody, George D, Dartois, Emmanuel, Dazzi, Alexandre, De Gregorio, Bradley, Deniset-Besseau, Ariane, Duprat, Jean, Engrand, Cécile, Hashiguchi, Minako, Kilcoyne, A. L. David, Komatsu, Mutsumi, Martins, Zita, Mathurin, Jérémie, Montagnac, Gilles, Mostefaoui, Smail, Okumura, Taiga, Quirico, Eric, Remusat, Laurent, Sandford, Scott, Shigenaka, Miho, Suga, Hiroki, Takeichi, Yasuo, Tamenori, Yusuke, Verdier-Paoletti, Maximilien, Wakabayashi, Daisuke, Abe, Masanao, Kamide, Kanami, Miyazaki, Akiko, Nakato, Aiko, Nakazawa, Satoru, Nishimura, Masahiro, Okada, Tatsuaki, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Usui, Tomohiro, Yada, Toru, Yogata, Kasumi, Yoshikawa, Makoto, Yurimoto, Hisayoshi, Noguchi, Takaaki, Okazaki, Ryuji, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the H, C, and N isotopic compositions of microscale (0.2 to 2$\mu$m) organic matter in samples of asteroid Ryugu and the Orgueil CI carbonaceous chondrite. Three regolith particles of asteroid Ryugu, returned by the Hayabusa2 spacecraft, and several fragments of Orgueil were analyzed by NanoSIMS isotopic imaging. The isotopic distributions of the Ryugu samples from two different collection spots are closely similar to each other and to the Orgueil samples, strengthening the proposed Ryugu-CI chondrite connection. Most individual sub-$\mu$m organic grains have isotopic compositions within error of bulk values, but 2-8% of them are outliers exhibiting large isotopic enrichments or depletions in D, $^{15}$N, and/or $^{13}$C. The H, C and N isotopic compositions of the outliers are not correlated with each other: while some C-rich grains are both D- and $^{15}$N-enriched, many are enriched or depleted in one or the other system. This most likely points to a diversity in isotopic fractionation pathways and thus diversity in the local formation environments for the individual outlier grains. The observation of a relatively small population of isotopic outlier grains can be explained either by escape from nebular and/or parent body homogenization of carbonaceous precursor material or addition of later isotopic outlier grains. The strong chemical similarity of isotopically typical and isotopically outlying grains, as reflected by synchrotron x-ray absorption spectra, suggests a genetic connection and thus favors the former, homogenization scenario. However, the fact that even the least altered meteorites show the same pattern of a small population of outliers on top of a larger population of homogenized grains indicates that some or most of the homogenization occurred prior to accretion of the macromolecular organic grains into asteroidal parent bodies., Comment: Accepted for publication in Earth and Planetary Science Letters. 8 figures (plus 3 supplementary figs), two tables

Published
2024

6. Fermi surface topology and electronic transport properties of a chiral crystal NbGe$_2$ with strong electron-phonon interaction

Author

Sato, Yoshiki J., Nakamura, Ai, Nishinakayama, Rei, Okazaki, Ryuji, Harima, Hisatomo, and Aoki, Dai

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

We report the electronic structures and transport properties of a chiral crystal NbGe$_2$, which is a candidate for a coupled electron-phonon liquid. The electrical resistivity and thermoelectric power of NbGe$_2$ exhibit clear differences compared to those of NbSi2 even though both niobium ditetrelides are isostructural and isoelectronic. We discuss the intriguing transport properties of NbGe$_2$ based on a van Hove-type singularity in the density of states. The analysis of de Haas-van Alphen oscillations measured by the field modulation and magnetic torque methods reveals the detailed shape of the Fermi surface of NbGe$_2$ by comparison with the results of energy band structure calculations using a local density approximation. The electron and hole Fermi surfaces of NbGe$_2$ split into two because of the anti-symmetric spin-orbit interaction. The temperature dependence of quantum oscillations indicates that the effective mass is isotropically enhanced in NbGe$_2$ due to strong electron-phonon interaction., Comment: 9 pages, 7 figures, To be published in Phys. Rev. B

Published
2023

7. Analysis of Cation Composition in Dolomites on the Intact Particles Sampled from Asteroid Ryugu.

Author

Morita, Mayu, Yui, Hiroharu, Urashima, Shu-Hei, Onose, Morihiko, Komatani, Shintaro, Nakai, Izumi, Abe, Yoshinari, Terada, Yasuko, Homma, Hisashi, Motomura, Kazuko, Ichida, Kiyohiro, Yokoyama, Tetsuya, Nagashima, Kazuhide, Aléon, Jérôme, OD Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko, Hibiya, Yuki, Hidaka, Hiroshi, Hoppe, Peter, Huss, Gary, Iizuka, Tsuyoshi, Ireland, Trevor, Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Kouki, Kleine, Thorsten, Krot, Sasha, Liu, Ming-Chang, Masuda, Yuki, Moynier, Frédéric, Nguyen, Ann, Nittler, Larry, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Rocco, Tommaso, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard, Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Abstract

Characterization of the elemental distribution of samples with rough surfaces has been strongly desired for the analysis of various natural and artificial materials. Particularly for pristine and rare analytes with micrometer sizes embedded on specimen surfaces, non-invasive and matrix effect-free analysis is required without surface polishing treatment. To satisfy these requirements, we proposed a new method employing the sequential combination of two imaging modalities, i.e., microenergy-dispersive X-ray fluorescence (micro-XRF) and Raman micro-spectroscopy. The applicability of the developed method is tested by the quantitative analysis of cation composition in micrometer-sized carbonate grains on the surfaces of intact particles sampled directly from the asteroid Ryugu. The first step of micro-XRF imaging enabled a quick search for the sparsely scattered and micrometer-sized carbonates by the codistributions of Ca2+ and Mn2+ on the Mg2+- and Fe2+-rich phyllosilicate matrix. The following step of Raman micro-spectroscopy probed the carbonate grains and analyzed their cation composition (Ca2+, Mg2+, and Fe2+ + Mn2+) in a matrix effect-free manner via the systematic Raman shifts of the lattice modes. The carbonates were basically assigned to ferroan dolomite bearing a considerable amount of Fe2+ + Mn2+ at around 10 atom %. These results are in good accordance with the assignments reported by scanning electron microscopy-energy-dispersive X-ray spectroscopy, where the thin-sectioned and surface-polished Ryugu particles were applicable. The proposed method requires neither sectioning nor surface polishing; hence, it can be applied to the remote sensing apparatus on spacecrafts and planetary rovers. Furthermore, the non-invasive and matrix effect-free characterization will provide a reliable analytical tool for quantitative analysis of the elemental distribution on the samples with surface roughness and chemical heterogeneity at a micrometer scale, such as art paintings, traditional crafts with decorated shapes, as well as sands and rocks with complex morphologies in nature.

Published
2024

8. Carrier filtering effect for enhanced thermopower in a body-centered tetragonal ruthenate

Author

Otsuki, Ryota, Sato, Yoshiki J., Okazaki, Ryuji, Komine, Tomoya, Kurihara, Ryosuke, and Yaguchi, Hiroshi

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science, Condensed Matter - Superconductivity, Physics - Applied Physics
Abstract

Charged carriers in solids diffuse from hot to cold sides under temperature gradient to induce the thermoelectric voltage. Carrier filtering effect, which only passes either electrons or holes for the conduction process, is an efficient method to enhance such voltage, although it is challenging to experimentally realize it especially in conventional metals with weak energy dependence of the density of states near the Fermi level. Here we measure the in-plane and out-of-plane thermopower of the layered perovskite Sr$_2$RuO$_4$ single crystals above room temperature, and find that the out-of-plane thermopower is largely enhanced with increasing temperature, while the in-plane one seems to remain a temperature-independent constant value which is expected from the Heikes formula. The observed large out-of-plane thermopower may originate from the recently proposed intriguing hole filtering effect in the body-centered tetragonal system, in which the carrier hopping through the centered atom is essential. Thus, the present carrier filtering effect may be a universal property to be applicable in various materials belonging to such crystal system., Comment: 7 pages, 5 figures. Accepted for publication in Phys. Rev. Materials

Published
2023
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9. Mechanically exfoliated low-layered [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$]: A single-crystalline p-type transparent conducting oxide

Author

Okada, Reiji, Isomura, Hiroto, Sato, Yoshiki J., Okazaki, Ryuji, Inoue, Masayuki, and Yoshioka, Shinya

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons, Physics - Applied Physics, Physics - Optics
Abstract

Transparent conducting oxides (TCOs) are essential components of optoelectronic devices and various materials have been explored for highly efficient TCOs having a combination of high transmittance and low sheet resistance. Here, we focus on a misfit thermoelectric oxide [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$] and fabricate the transparent low-layered crystals by a mechanical tape-peeling method using the single-crystalline samples. From the transmittance measurement, we find that the thickness of low-layered samples is several orders of hundred nanometers, which is comparable with the estimation from the scanning electron microscopy images. Compared to the previous results on the polycrystalline and $c$-axis oriented transparent films, the electrical resistivity is reduced owing to the single-crystalline nature. The figure of merit for the transparent conducting materials in the present low-layered samples is then evaluated to be higher than the values in the previous reports. The present results on the low-layered single-crystalline [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$] may offer a unique class of multi-functional transparent thermoelectric oxides., Comment: 6 pages, 4 figures, 1 table. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing

Published
2023
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10. Breunnerite grain and magnesium isotope chemistry reveal cation partitioning during aqueous alteration of asteroid Ryugu

Author

Yoshimura, Toshihiro, Araoka, Daisuke, Naraoka, Hiroshi, Sakai, Saburo, Ogawa, Nanako O., Yurimoto, Hisayoshi, Morita, Mayu, Onose, Morihiko, Yokoyama, Tetsuya, Bizzarro, Martin, Tanaka, Satoru, Ohkouchi, Naohiko, Koga, Toshiki, Dworkin, Jason P., Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, Tsuda, Yuichi, Tachibana, Shogo, and Takano, Yoshinori

Published
2024
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11. Variations of organic functional chemistry in carbonaceous matter from the asteroid 162173 Ryugu

Author

De Gregorio, Bradley, Cody, George D., Stroud, Rhonda M., David Kilcoyne, A. L., Sandford, Scott, Le Guillou, Corentin, Nittler, Larry R., Barosch, Jens, Yabuta, Hikaru, Martins, Zita, Kebukawa, Yoko, Okumura, Taiga, Hashiguchi, Minako, Yamashita, Shohei, Takeichi, Yasuo, Takahashi, Yoshio, Wakabayashi, Daisuke, Engrand, Cécile, Bejach, Laure, Bonal, Lydie, Quirico, Eric, Remusat, Laurent, Duprat, Jean, Verdier-Paoletti, Maximilien, Mostefaoui, Smail, Komatsu, Mutsumi, Mathurin, Jérémie, Dazzi, Alexandre, Deniset-Besseau, Ariane, Dartois, Emmanuel, Tamenori, Yusuke, Suga, Hiroki, Montagnac, Gilles, Kamide, Kanami, Shigenaka, Miho, Matsumoto, Megumi, Enokido, Yuma, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Usui, Tomohiro, Abe, Masanao, Okada, Tatsuaki, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Yurimoto, Hisayoshi, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2024
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12. Primordial aqueous alteration recorded in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu

Author

Takano, Yoshinori, Naraoka, Hiroshi, Dworkin, Jason P., Koga, Toshiki, Sasaki, Kazunori, Sato, Hajime, Oba, Yasuhiro, Ogawa, Nanako O., Yoshimura, Toshihiro, Hamase, Kenji, Ohkouchi, Naohiko, Parker, Eric T., Aponte, José C., Glavin, Daniel P., Furukawa, Yoshihiro, Aoki, Junken, Kano, Kuniyuki, Nomura, Shin-ichiro M., Orthous-Daunay, Francois-Regis, Schmitt-Kopplin, Philippe, Yurimoto, Hisayoshi, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, Tsuda, Yuichi, and Tachibana, Shogo

Published
2024
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13. Nonmagnetic framboid and associated iron nanoparticles with a space-weathered feature from asteroid Ryugu

Author

Kimura, Yuki, Kato, Takeharu, Anada, Satoshi, Yoshida, Ryuji, Yamamoto, Kazuo, Tanigaki, Toshiaki, Akashi, Tetsuya, Kasai, Hiroto, Kurosawa, Kosuke, Nakamura, Tomoki, Noguchi, Takaaki, Sato, Masahiko, Matsumoto, Toru, Morita, Tomoyo, Kikuiri, Mizuha, Amano, Kana, Kagawa, Eiichi, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Yurimoto, Hisayoshi, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Watanabe, Sei-ichiro, Tsuda, Yuichi, and Tachibana, Shogo

Published
2024
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14. Water circulation in Ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sample.

Author

Yokoyama, Tetsuya, Wadhwa, Meenakshi, Iizuka, Tsuyoshi, Rai, Vinai, Gautam, Ikshu, Hibiya, Yuki, Masuda, Yuki, Haba, Makiko, Fukai, Ryota, Hines, Rebekah, Phelan, Nicole, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew, Di Rocco, Tommaso, Fujiya, Wataru, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary, Ichida, Kiyohiro, Ireland, Trevor, Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Koki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander, Liu, Ming-Chang, McKeegan, Kevin, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nagashima, Kazuhide, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Walker, Richard, Yamashita, Katsuyuki, Yoneda, Shigekazu, Young, Edward, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, Yurimoto, Hisayoshi, and Yin, Qing-Zhu

Abstract

Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between 54Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred [Formula: see text] after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.

Published
2023

15. Monoaxial Dzyaloshinskii-Moriya interaction-induced topological Hall effect in a new chiral-lattice magnet GdPt$_2$B

Author

Sato, Yoshiki J., Manako, Hikari, Okazaki, Ryuji, Yasui, Yukio, Nakamura, Ai, and Aoki, Dai

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We investigate the topological Hall effect (THE) in the monoaxial chiral crystal GdPt$_2$B, a recently discovered compound that exhibits putative helimagnetism below 87 K. The distinct THE was observed in GdPt2B in the magnetically ordered state. The scaling relations for anomalous and topological Hall conductivities differed from those of conventional models based on the scattering process. We further demonstrate the clear scaling behavior of the THE in a wide temperature range, which we attribute to the monoaxial Dzyaloshinskii-Moriya (DM) interaction under external magnetic fields perpendicular to the screw axis. The THE induced by the monoaxial DM interaction as well as the THE in a monoaxial chiral crystal of f-electron system are demonstrated in this study., Comment: 6 pages, 4 figures. To be published in Phys. Rev. B

Published
2023
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16. Abundant presolar grains and primordial organics preserved in carbon-rich exogenous clasts in asteroid Ryugu.

Author

Nguyen, Ann, Mane, Prajkta, Keller, Lindsay, Piani, Laurette, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew, Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary, Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor, Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander, Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Qin, Liping, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard, Yamashita, Katsuyuki, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, Yurimoto, Hisayoshi, and Yin, Qing-Zhu

Subjects
Carbon, Solar System, Meteoroids, Silicates
Abstract

Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC (~235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2%), and organics with C isotopic anomalies (0.2%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugus rubble pile origin.

Published
2023

17. Anomalous scaling law for thermoelectric transport of 2D-confined electrons in an organic molecular system

Author

Kouda, Naoki, Eguchi, Kyohei, Okazaki, Ryuji, and Tamura, Masafumi

Subjects
Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter, Condensed Matter - Strongly Correlated Electrons
Abstract

Confined electrons in low dimensions host desirable material functions for downscaled electronics as well as advanced energy technologies. Thermoelectricity is a most fascinating example, since the dimensionality modifies the electron density of states dramatically, leading to enhanced thermopower as experimentally examined in artificial two-dimensional (2D) structures. However, it is still an open question whether such an enhanced thermopower in low dimensions is realized in layered materials with strong 2D characters such as cuprates. Here, we report unusual enhancement of the thermopower in the layered organic compound $\alpha$-(BEDT-TTF)$_2$I$_3$, where BEDT-TTF stands for bis(ethylenedithio)-tetrathiafulvalene. We find that the slope in the Jonker plot (thermopower $S$ vs. logarithm of electrical conductivity $\log\sigma$) for $\alpha$-(BEDT-TTF)$_2$I$_3$ is significantly larger than that of conventional semiconductors. Moreover, the large slope is also seen in the related layered salt, demonstrating the impact of the 2D-confined carriers in the layered organics on thermoelectricity., Comment: 6 pages, 3 figures

Published
2022
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18. New Gd-based magnetic compound GdPt$_2$B with a chiral crystal structure

Author

Sato, Yoshiki J., Manako, Hikari, Homma, Yoshiya, Li, Dexin, Okazaki, Ryuji, and Aoki, Dai

Subjects
Condensed Matter - Materials Science, Condensed Matter - Strongly Correlated Electrons
Abstract

Herein, we report the discovery of a novel Gd-based magnetic compound GdPt$_2$B with a chiral crystal structure. X-ray diffraction and chemical composition analyses reveal a CePt$_2$B-type crystal structure (space group: $P6_422$) for GdPt$_2$B. Moreover, we successfully grew single crystals of GdPt$_2$B using the Czochralski method. Magnetization measurements and the Curie$-$Weiss analysis demonstrate that the ferromagnetic interaction is dominant in GdPt$_2$B. A clear transition is observed in the temperature dependence of electrical resistivity, magnetic susceptibility, and specific heat at $T_{\rm O}$ = 87 K. The magnetic phase diagram of GdPt$_2$B, which consists of a field-polarized ferromagnetic region and a magnetically ordered region, resembles those of known chiral helimagnets. Furthermore, magnetic susceptibility measurements reveal a possible spin reorientation within the magnetically ordered phase in magnetic fields perpendicular to the screw axis. The results demonstrate that GdPt$_2$B is a suitable platform for investigating the competing effects of ferromagnetic and antisymmetric exchange interactions in rare-earth-based chiral compounds., Comment: 9 pages, 7 figures. To be published in Phys. Rev. Materials

Published
2022
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19. Presolar stardust in asteroid Ryugu

Author

Barosch, Jens, Nittler, Larry R., Wang, Jianhua, Alexander, Conel M. O'D., De Gregorio, Bradley T., Engrand, Cécile, Kebukawa, Yoko, Nagashima, Kazuhide, Stroud, Rhonda M., Yabuta, Hikaru, Abe, Yoshinari, Aléon, Jérôme, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bejach, Laure, Bizzarro, Martin, Bonal, Lydie, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Cody, George D., Dartois, Emmanuel, Dauphas, Nicolas, Davis, Andrew M., Dazzi, Alexandre, Deniset-Besseau, Ariane, Di Rocco, Tommaso, Duprat, Jean, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hashiguchi, Minako, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kamide, Kanami, Kawasaki, Noriyuki, Kilcoyne, A. L. David, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Komatsu, Mutsumi, Krot, Alexander N., Liu, Ming-Chang, Martins, Zita, Masuda, Yuki, Mathurin, Jérémie, McKeegan, Kevin D., Montagnac, Gilles, Morita, Mayu, Mostefaoui, Smail, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nguyen, Ann N., Ohigashi, Takuji, Okumura, Taiga, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Quirico, Eric, Remusat, Laurent, Russell, Sara S., Sakamoto, Naoya, Sandford, Scott A., Schönbächler, Maria, Shigenaka, Miho, Suga, Hiroki, Tafla, Lauren, Takahashi, Yoshio, Takeichi, Yasuo, Tamenori, Yusuke, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Verdier-Paoletti, Maximilien, Wada, Sohei, Wadhwa, Meenakshi, Wakabayashi, Daisuke, Walker, Richard J., Yamashita, Katsuyuki, Yamashita, Shohei, Yin, Qing-Zhu, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nakazawa, Satoru, Nishimura, Masahiro, Okada, Tatsuaki, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yada, Toru, Yogata, Kasumi, Yoshikawa, Makoto, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Tachibana, Shogo, and Yurimoto, Hisayoshi

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We have conducted a NanoSIMS-based search for presolar material in samples recently returned from C-type asteroid Ryugu as part of JAXA's Hayabusa2 mission. We report the detection of all major presolar grain types with O- and C-anomalous isotopic compositions typically identified in carbonaceous chondrite meteorites: 1 silicate, 1 oxide, 1 O-anomalous supernova grain of ambiguous phase, 38 SiC, and 16 carbonaceous grains. At least two of the carbonaceous grains are presolar graphites, whereas several grains with moderate C isotopic anomalies are probably organics. The presolar silicate was located in a clast with a less altered lithology than the typical extensively aqueously altered Ryugu matrix. The matrix-normalized presolar grain abundances in Ryugu are 4.8$^{+4.7}_{-2.6}$ ppm for O-anomalous grains, 25$^{+6}_{-5}$ ppm for SiC grains and 11$^{+5}_{-3}$ ppm for carbonaceous grains. Ryugu is isotopically and petrologically similar to carbonaceous Ivuna-type (CI) chondrites. To compare the in situ presolar grain abundances of Ryugu with CI chondrites, we also mapped Ivuna and Orgueil samples and found a total of SiC grains and 6 carbonaceous grains. No O-anomalous grains were detected. The matrix-normalized presolar grain abundances in the CI chondrites are similar to those in Ryugu: 23 $^{+7}_{-6}$ ppm SiC and 9.0$^{+5.3}_{-4.6}$ ppm carbonaceous grains. Thus, our results provide further evidence in support of the Ryugu-CI connection. They also reveal intriguing hints of small-scale heterogeneities in the Ryugu samples, such as locally distinct degrees of alteration that allowed the preservation of delicate presolar material., Comment: 12 pages, 3 figures, 2 tables. Published in ApJL

Published
2022
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20. Influx of nitrogen-rich material from the outer Solar System indicated by iron nitride in Ryugu samples

Author

Matsumoto, Toru, Noguchi, Takaaki, Miyake, Akira, Igami, Yohei, Haruta, Mitsutaka, Seto, Yusuke, Miyahara, Masaaki, Tomioka, Naotaka, Saito, Hikaru, Hata, Satoshi, Harries, Dennis, Takigawa, Aki, Nakauchi, Yusuke, Tachibana, Shogo, Nakamura, Tomoki, Matsumoto, Megumi, Ishii, Hope A., Bradley, John P., Ohtaki, Kenta, Dobrică, Elena, Leroux, Hugues, Le Guillou, Corentin, Jacob, Damien, de la Peña, Francisco, Laforet, Sylvain, Marinova, Maya, Langenhorst, Falko, Beck, Pierre, Phan, Thi H. V., Rebois, Rolando, Abreu, Neyda M., Gray, Jennifer, Zega, Thomas, Zanetta, Pierre-M., Thompson, Michelle S., Stroud, Rhonda, Burgess, Kate, Cymes, Brittany A., Bridges, John C., Hicks, Leon, Lee, Martin R., Daly, Luke, Bland, Phil A., Zolensky, Michael E., Frank, David R., Martinez, James, Tsuchiyama, Akira, Yasutake, Masahiro, Matsuno, Junya, Okumura, Shota, Mitsukawa, Itaru, Uesugi, Kentaro, Uesugi, Masayuki, Takeuchi, Akihisa, Sun, Mingqi, Enju, Satomi, Michikami, Tatsuhiro, Yurimoto, Hisayoshi, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2024
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21. Enhanced Seebeck coefficient through the magnetic fluctuations in Sr$_2$Ru$_{1-x}M_x$O$_4$ ($M = $ Co, Mn)

Author

Yamanaka, Takayoshi, Okazaki, Ryuji, and Yaguchi, Hiroshi

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

The layered perovskite Sr$_2$RuO$_4$ is a most intensively studied superconductor, but its pairing mechanism, which is often coupled intimately with magnetic fluctuations in correlated materials, is still an open question. Here we present a systematic evolution of the Seebeck coefficient in Co- and Mn-substituted Sr$_2$RuO$_4$ single crystals, in which ferromagnetic and antiferromagnetic glassy states respectively emerge in proximity to the superconducting phase of the parent compound. We find that the Seebeck coefficient $S$ divided by temperature $T$, $S/T$, shows a maximum near characteristic temperatures seen in the irreversible magnetization $M_{\rm ir}$ in both of the Co- and Mn-substituted crystals, demonstrating both of the ferromagnetic and antiferromagnetic fluctuations to enhance the Seebeck coefficient. Interestingly, $S/T$ increases with lowering temperature in the parent compound, reminiscent of non-Fermi-liquid behavior, indicating an essential role of coexisting ferromagnetic and antiferromagnetic fluctuations for the itinerant electrons in Sr$_2$RuO$_4$., Comment: 7 pages, 4 figures

Published
2022
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22. Oxygen isotopes of anhydrous primary minerals show kinship between asteroid Ryugu and comet 81P/Wild2

Author

Kawasaki, Noriyuki, Nagashima, Kazuhide, Sakamoto, Naoya, Matsumoto, Toru, Bajo, Ken-ichi, Wada, Sohei, Igami, Yohei, Miyake, Akira, Noguchi, Takaaki, Yamamoto, Daiki, Russell, Sara S, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel M O’D, Amari, Sachiko, Amelin, Yuri, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M, Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R, Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R, Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kita, Noriko T, Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N, Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin D, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wadhwa, Meenakshi, Walker, Richard J, Yamashita, Katsuyuki, Yin, Qing-Zhu, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward D, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Subjects
Earth Sciences, Physical Sciences, Space Sciences, Geology, Prevention
Abstract

The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically and mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary minerals in Ryugu and CI chondrites exhibit a bimodal distribution of oxygen isotopic compositions: 16O-rich (associated with refractory inclusions) and 16O-poor (associated with chondrules). Both the 16O-rich and 16O-poor minerals probably formed in the inner solar protoplanetary disk and were subsequently transported outward. The abundance ratios of the 16O-rich to 16O-poor minerals in Ryugu and CI chondrites are higher than in other carbonaceous chondrite groups but are similar to that of comet 81P/Wild2, suggesting that Ryugu and CI chondrites accreted in the outer Solar System closer to the accretion region of comets.

Published
2022

23. Contribution of Ryugu-like material to Earths volatile inventory by Cu and Zn isotopic analysis.

Author

Paquet, Marine, Moynier, Frederic, Yokoyama, Tetsuya, Dai, Wei, Hu, Yan, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew, Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary, Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor, Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander, Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin, Morita, Mayu, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard, Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Subjects
CI chondrites, Cu isotopes, Hayabusa2, Ryugu, Zn isotopes, volatile elements
Abstract

Initial analyses showed that asteroid Ryugus composition is close to CI (Ivuna-like) carbonaceous chondrites -the chemically most primitive meteorites, characterized by near-solar abundances for most elements. However, some isotopic signatures (e.g., Ti, Cr) overlap with other carbonaceous chondrite (CC) groups, so the details of the link between Ryugu and the CI chondrites are not fully clear yet. Here we show that Ryugu and CI chondrites have the same zinc and copper isotopic composition. As the various chondrite groups have very distinct Zn and Cu isotopic signatures, our results point at a common genetic heritage between Ryugu and CI chondrites, ruling out any affinity with other CC groups. Since Ryugus pristine samples match the solar elemental composition for many elements, their Zn and Cu isotopic compositions likely represent the best estimates of the solar composition. Earths mass-independent Zn isotopic composition is intermediate between Ryugu/CC and non-carbonaceous chondrites, suggesting a contribution of Ryugu-like material to Earths budgets of Zn and other moderately volatile elements.

Published
2022

24. Ryugus nucleosynthetic heritage from the outskirts of the Solar System.

Author

Hopp, Timo, Dauphas, Nicolas, Abe, Yoshinari, Aléon, Jérôme, OD Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-Ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard, Chaussidon, Marc, Choi, Byeon-Gak, Davis, Andrew, Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko, Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary, Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor, Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko, Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander, Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin, Morita, Mayu, Motomura, Kazuko, Moynier, Frédéric, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara, Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard, Yamashita, Katsuyuki, Yin, Qing-Zhu, Yokoyama, Tetsuya, Yoneda, Shigekazu, Young, Edward, Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-Ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Abstract

Little is known about the origin of the spectral diversity of asteroids and what it says about conditions in the protoplanetary disk. Here, we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable from Ivuna-type (CI) chondrites, which are distinct from all other carbonaceous chondrites. Iron isotopes, therefore, demonstrate that Ryugu and CI chondrites formed in a reservoir that was different from the source regions of other carbonaceous asteroids. Growth and migration of the giant planets destabilized nearby planetesimals and ejected some inward to be implanted into the Main Belt. In this framework, most carbonaceous chondrites may have originated from regions around the birthplaces of Jupiter and Saturn, while the distinct isotopic composition of CI chondrites and Ryugu may reflect their formation further away in the disk, owing their presence in the inner Solar System to excitation by Uranus and Neptune.

Published
2022

25. Prominent electron-hole asymmetry in thermoelectric transport of LaCoO$_3$

Author

Okazaki, Ryuji and Tomiyasu, Keisuke

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

We have measured the electrical resistivity and the thermopower of the electron-doped perovskite cobaltites LaCo$_{1-y}$Te$_y$O$_3$. In contrast to the hole-doped systems such as metallic ferromagnets La$_{1-x}M_x$CoO$_3$ ($M$ = Ca, Sr, Ba), the electron-doped samples show an insulating behavior even in a heavily doped range due to a spin-state blockade mechanism that an electron hopping from high-spin Co$^{2+}$ to low-spin Co$^{3+}$ site is energetically suppressed. We find that, despite the electron doping, the thermopower shows relatively large positive values above $y=0.05$, strikingly distinct from the hole-doped case where it comes close to zero with doping. This prominent electron-hole asymmetry seen in the thermopower originates from a bipolar conduction which consists of a slight amount of mobile holes and the main immobile electrons, demonstrating an impact of spin-state blockade on thermoelectric transport., Comment: 6 pages, 4 figures

Published
2022
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26. Third-order Electrical Conductivity of the Charge-ordered Organic Salt $\alpha$-(BEDT-TTF)$_2$I$_3$

Author

Ishii, Mayu, Okazaki, Ryuji, and Tamura, Masafumi

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

We performed third-order electrical conductivity measurements on the organic conductor $\alpha$-(BEDT-TTF)$_2$I$_3$ using an ac bridge technique sensitive to nonlinear signals. Third-order conductance $G_3$ is clearly observed even at low electric fields, and interestingly, $G_3$ is critically enhanced above the charge-order transition temperature $T_{\rm CO}=136$~K. The observed frequency dependence of $G_3$ is incompatible with a percolation model, in which a Joule heating in a random resistor network is relevant to the nonlinear conduction. We instead argue the nonlinearity of the relaxation time according to a phenomenological model on the mobility in materials with large dielectric constants, and find that the third-order conductance $G_3$ corresponds to the third-order electric susceptibility $\chi_3$. Since the nonlinear susceptibility is known as a probe for higher-order multipole ordering, the present observation of the divergent behavior of $G_3$ above $T_{\rm CO}$ reveals an underlying quadrupole instability at the charge-order transition of the organic system., Comment: 5 pages, 3 figures

Published
2022
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27. Pyrrhotites in asteroid 162173 Ryugu: Records of the initial changes on their surfaces with aqueous alteration

Author

Yui, Hiroharu, Urashima, Shu-hei, Onose, Morihiko, Morita, Mayu, Komatani, Shintaro, Nakai, Izumi, Abe, Yoshinari, Terada, Yasuko, Homma, Hisashi, Motomura, Kazuko, Ichida, Kiyohiro, Yokoyama, Tetsuya, Nagashima, Kazuhide, Aléon, Jérôme, M. O’D. Alexander, Conel, Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Hoppe, Peter, Huss, Gary R., Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Krot, Sasha, Liu, Ming-Chang, Masuda, Yuki, Moynier, Frédéric, Nguyen, Ann, Nittler, Larry, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Di Rocco, Tommaso, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2024
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28. Three-dimensional textures of Ryugu samples and their implications for the evolution of aqueous alteration in the Ryugu parent body

Author

Tsuchiyama, Akira, Matsumoto, Megumi, Matsuno, Junya, Yasutake, Masahiro, Nakamura, Tomoki, Noguchi, Takaaki, Miyake, Akira, Uesugi, Kentaro, Takeuchi, Akihisa, Okumura, Shota, Fujioka, Yuri, Sun, Mingqi, Takigawa, Aki, Matsumoto, Toru, Enju, Satomi, Mitsukawa, Itaru, Enokido, Yuma, Kawamoto, Tatsuhiko, Mikouchi, Takeshi, Michikami, Tatsuhiro, Morita, Tomoyo, Kikuiri, Mizuha, Amano, Kana, Kagawa, Eiichi, Rubino, Stefano, Dionnet, Zelia, Aléon-Toppani, Alice, Brunetto, Rosario, Zolensky, Michael E., Nakano, Tsukasa, Nakano, Naoto, Yurimoto, Hisayoshi, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Nakazawa, Satoru, Terui, Fuyuto, Tachibana, Shogo, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2024
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29. Enantioselective three-dimensional high-performance liquid chromatographic determination of amino acids in the Hayabusa2 returned samples from the asteroid Ryugu

Author

Furusho, Aogu, Ishii, Chiharu, Akita, Takeyuki, Oyaide, Mai, Mita, Masashi, Naraoka, Hiroshi, Takano, Yoshinori, Dworkin, Jason P., Oba, Yasuhiro, Koga, Toshiki, Fukushima, Kazuhiko, Aoki, Dan, Hashiguchi, Minako, Mita, Hajime, Chikaraishi, Yoshito, Ohkouchi, Naohiko, Ogawa, Nanako O., Sakai, Saburo, Glavin, Daniel P., Elsila, Jamie E., Parker, Eric T., Aponte, José C., McLain, Hannah L., Orthous-Daunay, Francois-Regis, Vuitton, Véronique, Thissen, Roland, Wolters, Cédric, Schmitt-Kopplin, Philippe, Ruf, Alexander, Isa, Junko, Hertkorn, Norbert, Eiler, John M., Yoshimura, Toshihiro, Sugahara, Haruna, Graham, Heather V., Furukawa, Yoshihiro, Araoka, Daisuke, Tanaka, Satoru, Yoshikawa, Takaaki, Kabashima, Fumie, Sasaki, Kazunori, Sato, Hajime, Yamazaki, Tomoya, Onose, Morihiko, Morita, Mayu, Kimura, Yuki, Kano, Kuniyuki, Aoki, Junken, Fujishima, Kosuke, Nomura, Shin-ichiro, Tachibana, Shogo, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Yurimoto, Hisayoshi, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Okada, Tatsuaki, Watanabe, Sei-ichiro, Tsuda, Yuichi, and Hamase, Kenji

Published
2024
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30. Correlated IR-SEM-TEM studies of three different grains from Ryugu: From the initial material to post-accretional processes

Author

Aléon-Toppani, Alice, Brunetto, Rosario, Dionnet, Zélia, Rubino, Stefano, Baklouti, Donia, Brisset, François, Vallet, Maxime, Heripre, Eva, Nakamura, Tomoki, Lantz, Cateline, Djouadi, Zahia, Borondics, Ferenc, Sandt, Christophe, Troadec, David, Mivumbi, Obadias, Matsumoto, Megumi, Amano, Kana, Morita, Tomoyo, Yurimoto, Hisayoshi, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohira, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2024
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31. Pervasive aqueous alteration in the early Solar System revealed by potassium isotopic variations in Ryugu samples and carbonaceous chondrites

Author

Hu, Yan, Moynier, Frédéric, Dai, Wei, Paquet, Marine, Yokoyama, Tetsuya, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel M. O'D., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Koki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, Morita, Mayu, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2024
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32. The thermal history of Ryugu based on Raman characterization of Hayabusa2 samples

Author

Bonal, Lydie, Quirico, Eric, Montagnac, Gilles, Komatsu, Mutsumi, Kebukawa, Yoko, Yabuta, Hikaru, Amano, Kana, Barosch, Jens, Bejach, Laure, Cody, George D., Dartois, Emmanuel, Dazzi, Alexandre, De Gregorio, Bradley, Deniset-Besseau, Ariane, Duprat, Jean, Engrand, Cécile, Hashiguchi, Minako, Kamide, Kanami, Kilcoyne, David, Martins, Zita, Mathurin, Jérémie, Mostefaoui, Smail, Nittler, Larry, Ohigashi, Takuji, Okumura, Taiga, Remusat, Laurent, Sandford, Scott, Shigenaka, Miho, Stroud, Rhonda, Suga, Hiroki, Takahashi, Yoshio, Takeichi, Yasuo, Tamenori, Yusuke, Verdier-Paoletti, Maximilien, Yamashita, Shohei, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Yurimoto, Hisayoshi, Tachibana, Shogo, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nakazawa, Satoru, Nishimura, Masahiro, Okada, Tatsuaki, Saiki, Takanao, Sakamoto, Kanako, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Usui, Tomohiro, Watanabe, Sei-ichiro, Yada, Toru, Yogata, Kasumi, and Yoshikawa, Makota

Published
2024
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33. A curation for uncontaminated Hayabusa2-returned samples in the extraterrestrial curation center of JAXA: from the beginning to present day

Author

Yada, Toru, Abe, Masanao, Nishimura, Masahiro, Sawada, Hirotaka, Okazaki, Ryuji, Takano, Yoshinori, Sakamoto, Kanako, Okada, Tatsuaki, Nakato, Aiko, Yoshitake, Miwa, Nakano, Yuki, Yogata, Kasumi, Miyazaki, Akiko, Furuya, Shizuho, Iwamae, Ayako S., Nakatsubo, Shunichi, Hatakeda, Kentaro, Hitomi, Yuya, Kumagai, Kazuya, Suzuki, Shino, Miura, Yayoi N., Ito, Motoo, Tomioka, Naotaka, Uesugi, Masayuki, Karouji, Yuzuru, Uesugi, Kentaro, Shirai, Naoki, Yamaguchi, Akira, Imae, Naoya, Naraoka, Hiroshi, Yamamoto, Yuhji, Tachibana, Shogo, Yurimoto, Hisayoshi, and Usui, Tomohiro

Published
2023
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35. Soluble organic matter Molecular atlas of Ryugu reveals cold hydrothermalism on C-type asteroid parent body

Author

Schmitt-Kopplin, Philippe, Hertkorn, Norbert, Harir, Mourad, Moritz, Franco, Lucio, Marianna, Bonal, Lydie, Quirico, Eric, Takano, Yoshinori, Dworkin, Jason P., Naraoka, Hiroshi, Tachibana, Shogo, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Yurimoto, Hisayoshi, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Okada, Tatsuaki, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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36. Space weathering acts strongly on the uppermost surface of Ryugu

Author

Matsuoka, Moe, Kagawa, Ei-ichi, Amano, Kana, Nakamura, Tomoki, Tatsumi, Eri, Osawa, Takahito, Hiroi, Takahiro, Milliken, Ralph, Domingue, Deborah, Takir, Driss, Brunetto, Rosario, Barucci, Antonella, Kitazato, Kohei, Sugita, Seiji, Fujioka, Yuri, Sasaki, Osamu, Kobayashi, Shiho, Iwata, Takahiro, Morota, Tomokatsu, Yokota, Yasuhiro, Kouyama, Toru, Honda, Rie, Kameda, Shingo, Cho, Yuichiro, Yoshioka, Kazuo, Sawada, Hirotaka, Hayakawa, Masahiko, Sakatani, Naoya, Yamada, Manabu, Suzuki, Hidehiko, Honda, Chikatoshi, Ogawa, Kazunori, Shirai, Kei, Lantz, Cateline, Rubino, Stefano, Yurimoto, Hisayoshi, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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37. Chemical evolution of primordial salts and organic sulfur molecules in the asteroid 162173 Ryugu

Author

Yoshimura, Toshihiro, Takano, Yoshinori, Naraoka, Hiroshi, Koga, Toshiki, Araoka, Daisuke, Ogawa, Nanako O., Schmitt-Kopplin, Philippe, Hertkorn, Norbert, Oba, Yasuhiro, Dworkin, Jason P., Aponte, José C., Yoshikawa, Takaaki, Tanaka, Satoru, Ohkouchi, Naohiko, Hashiguchi, Minako, McLain, Hannah, Parker, Eric T., Sakai, Saburo, Yamaguchi, Mihoko, Suzuki, Takahiro, Yokoyama, Tetsuya, Yurimoto, Hisayoshi, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, Tsuda, Yuichi, and Tachibana, Shogo

Published
2023
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38. Visualization of nanoscale magnetic domain states in the asteroid Ryugu

Author

Kimura, Yuki, Kato, Takeharu, Tanigaki, Toshiaki, Akashi, Tetsuya, Kasai, Hiroto, Anada, Satoshi, Yoshida, Ryuji, Yamamoto, Kazuo, Nakamura, Tomoki, Sato, Masahiko, Amano, Kana, Kikuiri, Mizuha, Morita, Tomoyo, Kagawa, Eiichi, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Yurimoto, Hisayoshi, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Watanabe, Sei-ichiro, Tsuda, Yuichi, and Tachibana, Shogo

Published
2023
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39. Uracil in the carbonaceous asteroid (162173) Ryugu

Author

Oba, Yasuhiro, Koga, Toshiki, Takano, Yoshinori, Ogawa, Nanako O., Ohkouchi, Naohiko, Sasaki, Kazunori, Sato, Hajime, Glavin, Daniel P., Dworkin, Jason P., Naraoka, Hiroshi, Tachibana, Shogo, Yurimoto, Hisayoshi, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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40. PAHs, hydrocarbons, and dimethylsulfides in Asteroid Ryugu samples A0106 and C0107 and the Orgueil (CI1) meteorite

Author

Aponte, José C., Dworkin, Jason P., Glavin, Daniel P., Elsila, Jamie E., Parker, Eric T., McLain, Hannah L., Naraoka, Hiroshi, Okazaki, Ryuji, Takano, Yoshinori, Tachibana, Shogo, Dong, Guannan, Zeichner, Sarah S., Eiler, John M., Yurimoto, Hisayoshi, Nakamura, Tomoki, Yabuta, Hikaru, Terui, Fuyuto, Noguchi, Takaaki, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Nakazawa, Satoru, Tsuda, Yuichi, and Watanabe, Sei-ichiro

Published
2023
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41. Small grains from Ryugu: handling and analysis pipeline for infrared synchrotron microspectroscopy

Author

Rubino, Stefano, Dionnet, Zélia, Aléon-Toppani, Alice, Brunetto, Rosario, Nakamura, Tomoki, Baklouti, Donia, Djouadi, Zahia, Lantz, Cateline, Mivumbi, Obadias, Borondics, Ferenc, Lefrançois, Stephane, Sandt, Christophe, Capitani, Francesco, Héripré, Eva, Troadec, David, Matsumoto, Megumi, Amano, Kana, Morita, Tomoyo, Yurimoto, Hisayoshi, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Watanabe, Seiichiro, and Tsuda, Yuichi

Published
2023
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42. Chondrule-like objects and Ca-Al-rich inclusions in Ryugu may potentially be the oldest Solar System materials

Author

Nakashima, Daisuke, Nakamura, Tomoki, Zhang, Mingming, Kita, Noriko T., Mikouchi, Takashi, Yoshida, Hideto, Enokido, Yuma, Morita, Tomoyo, Kikuiri, Mizuha, Amano, Kana, Kagawa, Eiichi, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Nakazawa, Satoru, Terui, Fuyuto, Yurimoto, Hisayoshi, Noguchi, Takaaki, Yabuta, Hikaru, Naraoka, Hiroshi, Okazaki, Ryuji, Sakamoto, Kanako, Watanabe, Sei-ichiro, Tachibana, Shogo, and Tsuda, Yuichi

Published
2023
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43. The spatial distribution of soluble organic matter and their relationship to minerals in the asteroid (162173) Ryugu

Author

Hashiguchi, Minako, Aoki, Dan, Fukushima, Kazuhiko, Naraoka, Hiroshi, Takano, Yoshinori, Dworkin, Jason P., Dworkin, Karin E., Aponte, José C., Elsila, Jamie E., Eiler, John M., Furukawa, Yoshihiro, Furusho, Aogu, Glavin, Daniel P., Graham, Heather V., Hamase, Kenji, Hertkorn, Norbert, Isa, Junko, Koga, Toshiki, McLain, Hannah L., Mita, Hajime, Oba, Yasuhiro, Ogawa, Nanako O., Ohkouchi, Naohiko, Orthous-Daunay, Francois-Regis, Parker, Eric T., Ruf, Alexander, Sakai, Saburo, Schmitt-Kopplin, Philippe, Sugahara, Haruna, Thissen, Roland, Vuitton, Véronique, Wolters, Cédric, Yoshimura, Toshihiro, Yurimoto, Hisayoshi, Nakamura, Tomoki, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Sakamoto, Kanako, Tachibana, Shogo, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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44. A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

Author

Noguchi, Takaaki, Matsumoto, Toru, Miyake, Akira, Igami, Yohei, Haruta, Mitsutaka, Saito, Hikaru, Hata, Satoshi, Seto, Yusuke, Miyahara, Masaaki, Tomioka, Naotaka, Ishii, Hope A., Bradley, John P., Ohtaki, Kenta K., Dobrică, Elena, Leroux, Hugues, Le Guillou, Corentin, Jacob, Damien, de la Peña, Francisco, Laforet, Sylvain, Marinova, Maya, Langenhorst, Falko, Harries, Dennis, Beck, Pierre, Phan, Thi H. V., Rebois, Rolando, Abreu, Neyda M., Gray, Jennifer, Zega, Thomas, Zanetta, Pierre-M., Thompson, Michelle S., Stroud, Rhonda, Burgess, Kate, Cymes, Brittany A., Bridges, John C., Hicks, Leon, Lee, Martin R., Daly, Luke, Bland, Phil A., Zolensky, Michael E., Frank, David R., Martinez, James, Tsuchiyama, Akira, Yasutake, Masahiro, Matsuno, Junya, Okumura, Shota, Mitsukawa, Itaru, Uesugi, Kentaro, Uesugi, Masayuki, Takeuchi, Akihisa, Sun, Mingqi, Enju, Satomi, Takigawa, Aki, Michikami, Tatsuhiro, Nakamura, Tomoki, Matsumoto, Megumi, Nakauchi, Yusuke, Abe, Masanao, Arakawa, Masahiko, Fujii, Atsushi, Hayakawa, Masahiko, Hirata, Naru, Hirata, Naoyuki, Honda, Rie, Honda, Chikatoshi, Hosoda, Satoshi, Iijima, Yu-ichi, Ikeda, Hitoshi, Ishiguro, Masateru, Ishihara, Yoshiaki, Iwata, Takahiro, Kawahara, Kousuke, Kikuchi, Shota, Kitazato, Kohei, Matsumoto, Koji, Matsuoka, Moe, Mimasu, Yuya, Miura, Akira, Morota, Tomokatsu, Nakazawa, Satoru, Namiki, Noriyuki, Noda, Hirotomo, Noguchi, Rina, Ogawa, Naoko, Ogawa, Kazunori, Okada, Tatsuaki, Okamoto, Chisato, Ono, Go, Ozaki, Masanobu, Saiki, Takanao, Sakatani, Naoya, Sawada, Hirotaka, Senshu, Hiroki, Shimaki, Yuri, Shirai, Kei, Sugita, Seiji, Takei, Yuto, Takeuchi, Hiroshi, Tanaka, Satoshi, Tatsumi, Eri, Terui, Fuyuto, Tsukizaki, Ryudo, Wada, Koji, Yamada, Manabu, Yamada, Tetsuya, Yamamoto, Yukio, Yano, Hajime, Yokota, Yasuhiro, Yoshihara, Keisuke, Yoshikawa, Makoto, Yoshikawa, Kent, Fukai, Ryohta, Furuya, Shizuho, Hatakeda, Kentaro, Hayashi, Tasuku, Hitomi, Yuya, Kumagai, Kazuya, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Soejima, Hiromichi, Suzuki, Ayako I., Usui, Tomohiro, Yada, Toru, Yamamoto, Daiki, Yogata, Kasumi, Yoshitake, Miwa, Connolly, Jr, Harold C., Lauretta, Dante S., Yurimoto, Hisayoshi, Nagashima, Kazuhide, Kawasaki, Noriyuki, Sakamoto, Naoya, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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45. Contribution of Ryugu-like material to Earth’s volatile inventory by Cu and Zn isotopic analysis

Author

Paquet, Marine, Moynier, Frederic, Yokoyama, Tetsuya, Dai, Wei, Hu, Yan, Abe, Yoshinari, Aléon, Jérôme, O’D. Alexander, Conel M., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Ito, Motoo, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Kleine, Thorsten, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, McKeegan, Kevin D., Morita, Mayu, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nesvorný, David, Nguyen, Ann N., Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi

Published
2023
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46. Extraterrestrial amino acids and amines identified in asteroid Ryugu samples returned by the Hayabusa2 mission

Author

Parker, Eric T., McLain, Hannah L., Glavin, Daniel P., Dworkin, Jason P., Elsila, Jamie E., Aponte, José C., Naraoka, Hiroshi, Takano, Yoshinori, Tachibana, Shogo, Yabuta, Hikaru, Yurimoto, Hisayoshi, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Nakazawa, Satoru, Tsuda, Yuichi, Terui, Fuyuto, Noguchi, Takaaki, Okazaki, Ryuji, Watanabe, Sei-ichiro, and Nakamura, Tomoki

Published
2023
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47. Nonequilibrium spherulitic magnetite in the Ryugu samples

Author

Dobrică, Elena, Ishii, Hope A., Bradley, John P., Ohtaki, Kenta, Brearley, Adrian J., Noguchi, Takaaki, Matsumoto, Toru, Miyake, Akira, Igami, Yohei, Haruta, Mitsutaka, Saito, Hikaru, Hata, Satoshi, Seto, Yusuke, Miyahara, Masaaki, Tomioka, Naotaka, Leroux, Hugues, Le Guillou, Corentin, Jacob, Damien, de la Peña, Francisco, Laforet, Sylvain, Marinova, Maya, Langenhorst, Falko, Harries, Dennis, Beck, Pierre, Phan, Thi H.V., Rebois, Rolando, Abreu, Neyda M., Gray, Jennifer, Zega, Thomas, Zanetta, Pierre-M., Thompson, Michelle S., Stroud, Rhonda, Burgess, Kate, Cymes, Brittany A., Bridges, John C., Hicks, Leon, Lee, Martin R., Daly, Luke, Bland, Phil A., Zolensky, Michael E., Frank, David R., Martinez, James, Tsuchiyama, Akira, Yasutake, Masahiro, Matsuno, Junya, Okumura, Shota, Mitsukawa, Itaru, Uesugi, Kentaro, Uesugi, Masayuki, Takeuchi, Akihisa, Sun, Mingqi, Enju, Satomi, Takigawa, Aki, Michikami, Tatsuhiro, Nakamura, Tomoki, Matsumoto, Megumi, Nakauchi, Yusuke, Yurimoto, Hisayoshi, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, Usui, Tomohiro, Yoshikawa, Makoto, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Nakazawa, Satoru, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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48. Enhanced Seebeck coefficient by a filling-induced Lifshitz transition in KxRhO2

Author

Ito, Naoko, Ishii, Mayu, and Okazaki, Ryuji

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

We have systematically measured the transport properties in the layered rhodium oxide K$_{x}$RhO$_{2}$ single crystals ($0.5\lesssim x \lesssim 0.67$), which is isostructural to the thermoelectric oxide Na$_{x}$CoO$_{2}$. We find that below $x = 0.64$ the Seebeck coefficient is anomalously enhanced at low temperatures with increasing $x$, while it is proportional to the temperature like a conventional metal above $x=0.65$, suggesting an existence of a critical content $x^{*} \simeq 0.65$. For the origin of this anomalous behavior, we discuss a filling-induced Lifshitz transition, which is characterized by a sudden topological change in the cylindrical hole Fermi surfaces at the critical content $x^*$., Comment: 5 pages, 5 figures, to be published in Phys. Rev. B

Published
2019
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49. Enhanced thermopower via spin-state modification

Author

Takahashi, Hidefumi, Ishiwata, Shintaro, Okazaki, Ryuji, Yasui, Yukio, and Terasaki, Ichiro

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

We investigated the effect of pressure on the magnetic and thermoelectric properties of Sr$_{3.1}$Y$_{0.9}$Co$_{4}$O$_{10+\delta }$. The magnetization is reduced with the application of pressure, reflecting the spin-state modification of the Co$^{3+}$ ions into the nonmagnetic low-spin state. Accordingly, with increasing pressure, the Seebeck coefficient is enhanced, especially at low temperatures, at which the effect of pressure on the spin state becomes significant. These results indicate that the spin-orbital entropy is a key valuable for the thermoelectric properties of the strongly correlated cobalt oxides., Comment: 5 pages, 5 figures

Published
2018
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50. Measurement of Microscopic Thermal Diffusivity Distribution for Ryugu Sample by Infrared Lock-in Periodic Heating Method

Author

Ishizaki, Takuya, Nagano, Hosei, Tanaka, Satoshi, Sakatani, Naoya, Nakamura, Tomoki, Okada, Tatsuaki, Fujita, Ryohei, Alasli, Abdulkareem, Morita, Tomoyo, Kikuiri, Mizuha, Amano, Kana, Kagawa, Eiichi, Yurimoto, Hisayoshi, Noguchi, Takaaki, Okazaki, Ryuji, Yabuta, Hikaru, Naraoka, Hiroshi, Sakamoto, Kanako, Tachibana, Shogo, Watanabe, Sei-ichiro, and Tsuda, Yuichi

Published
2023
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