研究者データベース
原口 祐哉HARAGUCHI Yuyaハラグチ ユウヤ
| ■所属部署名 | 工学研究院 先端物理工学部門 | |||
| ■職名 | 助教 | |||
Last Updated :2025/04/10
業績情報
氏名・連絡先
氏名
ハラグチ ユウヤ, 原口 祐哉, HARAGUCHI Yuya生年
1989eメールアドレス
chiyuya3
go.tuat.ac.jp個人ホームページ
https://sites.google.com/site/chiyuyachiyuya
主たる所属・職名
工学研究院 先端物理工学部門, 助教
その他の所属
経歴
- 東京農工大学
工学研究科
助教
自 2019年03月01日 - 東京大学
物性研究所
特任研究員
自 2017年04月01日, 至 2019年02月28日 - 京都大学
大学院理学研究科
日本学術振興会特別研究員
自 2016年04月01日, 至 2017年03月31日
学歴
研究分野
研究キーワード
研究テーマ
担当授業科目
科学研究費助成事業
- 学術変革領域研究(A)（公募研究）
分子アニオン化合物を前駆体とする固相メタセシスの開拓と超セラミックス量子物質創製
自 2023年, 至 2024年 - 若手研究
速度論的結晶場エンジニアリングで拓く新奇スピン軌道結合量子相
自 2022年, 至 2024年 - 若手研究
低温複分解を用いたキタエフ型磁性体のスピン軌道結合効果の制御と異常物性探索
自 2019年, 至 2022年 - 学術変革領域研究(A)（公募研究）
分子アニオン化合物を前駆体とする固相メタセシスの開拓と超セラミックス量子物質創製
論文
- Polymorphism and magnetism in a Kitaev honeycomb cobaltate KCoAsO4
Yuya Haraguchi, Daisuke Nishio-Hamane, Hiroko Aruga Katori
Scientific Reports
2025年01月21日, 研究論文（学術雑誌）, 共同, 15, DOI(公開)(r-map), 2624 - CaCo2TeO6: A topochemically prepared 3d7 honeycomb Kitaev magnet
Yuya Haraguchi, Yuto Yoshida, Akira Matsuo, Koichi Kindo, Hiroko Aruga Katori
Physical Review B
American Physical Society
2024年11月14日, 研究論文（学術雑誌）, 共同, 110, 18, DOI(公開)(r-map), 184411-1, 184411-9 - Molecular Orbital Electronic Instability in the van der Waals Kagomé Semiconductor Nb3Cl8: Exploring Future Directions
Yuya Haraguchi, and Kazuyoshi Yoshimura
Journal of the Physical Society of Japan
The Physical Society of Japan
2024年09月04日, 研究論文（学術雑誌）, 共同, 93, 11, DOI(公開)(r-map), 111002-1, 111002-9 - Magnetic ordering of the Mo3O8-type cluster Mott insulator Na3Sc2(MoO4)2Mo3O8 with spin-1/2 triangular lattice prepared via optimal synthesis
Yuya Haraguchi, Daigo Ishikita & Hiroko Aruga Katori
Physical Review Materials
American Physical Society
2024年08月15日, 研究論文（学術雑誌）, 共同, 8, DOI(公開)(r-map), 084409 - Charge fluctuations in a cluster Mott state: Hard x-ray photoemission study on a breathing kagome magnet Nb3Cl8
R. Nakamura, D. Takegami, K. Fujinuma, M. Nakamura, M. Ferreira-Carvalho, A. Melendez-Sans, M. Yoshimura, K. -D. Tsuei, Y. Haraguchi, H. Katori, L. H. Tjeng, T. Mizokawa
Physical Review B
American Physical Society
2024年08月15日, 研究論文（学術雑誌）, 共同, 110, DOI(公開)(r-map), L081109 - High-temperature magnetic anomaly via suppression of antisite disorder through synthesis route modification in a Kitaev candidate Cu2IrO3
Yuya Haraguchi, Daisuke Nishio-Hamane, Akira Matsuo, Koichi Kindo, Hiroko Aruga Katori
Journal of Physics: Condensed Matter
IOP Publishing Ltd
2024年07月08日, 研究論文（学術雑誌）, 共同, 36, DOI(公開)(r-map), 405801 - Impact of oxidation state on the valence-bond glass physics in the lithium-intercalated Mo3O8 cluster Mott insulators
Daigo Ishikita, Yuya Haraguchi, Hiroko Aruga Katori
Physical Review B
American Physical Society
2024年01月04日, 研究論文（学術雑誌）, 共同, 109, DOI(公開)(r-map), 024405-1, 024405-9 - Magnetic ordering in the Jeff = 0 nickelate NiRh2O4 prepared via a solid-state metathesis
Y. Haraguchi, Daisuke Nishio-Hamane, and H. Aruga Katori
Physical Review Materials
American Physical Society
In spinel-type nickelate NiRh2O4, magnetic ordering is observed upon the sample synthesized via kinetically controlled low-temperature solid-state metathesis, as opposed to previously reported samples obtained through conventional solid-state reaction. Our findings are based on a combination of bulk susceptibility and specific heat measurements that disclose a Neel transition temperature of T-N = 45 K in this material, which might feature spin-orbit entanglement in the tetragonally coordinated d(8) Mott insulators. The emergence of magnetic ordering upon alteration of the synthesis route indicates that the suppression of magnetic ordering in the previous sample was rooted in the cation mixing assisted by the entropy gain that results from high-temperature reactions. Furthermore, the J(eff) = 0 physics, instead of solely the spin-only S = 1, describes the observed enhancement of effective magnetic moment well. Overseeing all observations and speculations, we propose that the possible mechanism responsible for the emergent magnetic orderings in NiRh2O4 is the condensation of the J(eff) = 1 exciton, driven by the interplay of the tetragonal crystal field and superexchange interactions.
2023年08月30日, 研究論文（学術雑誌）, 共同, 7, 8, 2475-9953, DOI(公開)(r-map), 084413-1, 084413-7 - Magnetic-field-induced valence change in Eu ( Co 1 − x Ni x ) 2 P 2 up to 60 T
Raito Nakamura, Azumi Ishita, Jin Nakamura, Hiroto Ohta, Yuya Haraguchi, Hiroko Aruga Katori, Hajime Ishikawa, Akira Matsuo, Koichi Kindo, Minoru Nohara, and Akihiko Ikeda
Physical Review B
American Physical Society
The solid solution 122 compounds, Eu(Co1-xNix)2P2, show a valence transition between divalent state and intermediate valence states at Eu, which is firmly correlated to multiple degrees of freedom in the solid such as the isostructural transition between the collapsed tetragonal (cT) and uncollapsed tetragonal (ucT) structures, 3d magnetism, and the formation of P-P dimers. To gain insights into the correlated behavior, we investigate the effect of high magnetic fields on the samples of x = 0.4 and 0.5 using magnetostriction and magnetization measurements up to 60 T. The samples are in the Eu valence-fluctuating regime, where the possible structural transition from cT to ucT may be induced by the Eu valence change under the magnetic fields. For both samples, magnetostriction smoothly increases with increasing magnetic fields. The behavior is in good agreement with the calculated results using the interconfigurational fluctuation (ICF) model that describes the Eu valence change. This indicates that AL represents the change of the Eu valence state in these compounds. Magnetization curves for both compounds show good agreement with the ICF model at high magnetic fields. In contrast, in the lowmagnetic-field region, magnetization curves do not agree with the ICF model. These results indicate that the Eu valence changes manifest themselves in the magnetization curves at high magnetic fields and that the magnetism of the 3d electrons manifests itself in the magnetization at low magnetic fields. Hence, we conclude that the valence change occurs within the Eu valence fluctuation regime coupled with the cT structure. Thereby, we believe that the transition to ucT structure, which is firmly coupled with the divalent Eu state, does not occur within the magnetic field range of the present study. Even higher magnetic fields or pulsed magnetic fields with slower pulse durations may induce such large state changes in the present material, which is triggered by the Eu valence change under high magnetic fields.
2023年06月05日, 研究論文（学術雑誌）, 共同, 107, 15, 2469-9950, DOI(公開)(r-map), 235110-1, 235110-7 - Monoclinic Distortion in Hyperhoneycomb Kitaev Material β-ZnIrO3 Revealed by Improved Sample Quality
Yuya Haraguchi and Hiroko Aruga Katori
Chemistry Letters
The Chemical Society of Japan
The sample quality of the hyperhoneycomb lattice Kitaev magnet fl-ZnIrO3 was successfully improved by removing the maximum amount of moisture from the reaction ampoule. The X-ray diffraction structural analysis of the high-quality sample confirmed the presence of P21/c superlattice peaks of the Fddd structure in the original structural model. These peaks could not be distinguished due to the presence of impurities in the low -quality sample in a previous study. The structural analysis based on this monoclinic crystal structure model showed no chemical disorder, suggesting that the observed spin liquid type behavior is an intrinsic property unrelated to bond randomness. The details of the fl-ZnIrO3 structure revealed in this study will stimulate the further investigation of Kitaev physics.
2023年05月, 研究論文（学術雑誌）, 共同, 52, 5, 0366-7022, DOI(公開)(r-map), 404, 407 - Perfect kagome-lattice antiferromagnets with Jeff = 1/2: The Co2+-analogs of copper minerals volborthite and vesignieite
Y. Haraguchi, T. Ohnoda, A. Matsuo, K. Kindo, and H. Aruga Katori
Physical Review B
AMER PHYSICAL SOC
We report the synthesis, crystal structure, and magnetic properties of Co2+ kagome magnets Co3V2O7(OH)(2)middot2H(2)O and BaCo3(VO4)(2)(OH)(2), which can be recognized as Co analogs of the intensively researched quantum kagome magnet volborthite Cu3V2O7(OH)(2)middot2H(2)O and vesignieite BaCu3(VO4)(2)(OH)(2). For each compound, the ground state is seemingly A-type antiferromagnetic order. At low temperatures, applying a magnetic field causes a metamagneticlike transition described by the transition in which antiferromagnetically aligned canted moments change to ferromagnetically aligned ones. These ground and field-induced states include a canted ferromagnetic component perpendicular to the kagome planes favored by Dzyaloshinskii-Moriya interactions. These magnetic properties are well characterized by the J(eff) = 1/2 physics. Our findings will be a step toward clarifying the J(eff )= 1/2 kagome physics, which has not been thoroughly studied experimentally or theoretically.
2022年12月19日, 研究論文（学術雑誌）, 共同, 106, 21, 2469-9950, DOI(公開)(r-map), 214421 - 低温イオン交換を用いた新しいキタエフ物質の開発―固体化学の立場から見えてきたキタエフスピン液体の実現指針―
原口祐哉・香取浩子・道岡千城・植田浩明・吉村一良
固体物理
株式会社 アグネ技術センター
2022年11月22日, （MISC）総説・解説（商業誌）, 共同, 57, 681, 745, 756 - Honeycomb lattice iridate on the verge of Mott-collapse
Yuya Haraguchi, and Hiroko Aruga Katori
JOURNAL OF PHYSICS-CONDENSED MATTER
IOP Publishing Ltd
A new honeycomb lattice iridate (La,Na)IrO3 (approximate to LaNaIr2O6) is successfully synthesized from the spin-orbit coupled Mott insulator Na2IrO3 by replacing the interlayer Na+ ions with La3+ ions. (La,Na)IrO3 shows a finite Sommerfeld term in heat capacity and a -lnT dependence of resistivity, indicating a realization of a metallic state driven by a Mott collapse. Furthermore, crystal structure analysis reveals the formation of Ir zig-zag chains with metal-metal bonding, increasing kinetic energy resulting in the Mott collapse. This observation would be due to a Mott collapse induced in a J (eff) = 1/2 spin-orbit coupling Mott insulator with an Ir honeycomb lattice by topochemical control of the ionic configuration.
2022年11月16日, 研究論文（学術雑誌）, 共同, 34, 46, 0953-8984, DOI(公開)(r-map), 465602-1, 465602-7 - Improvement of optical transmittance of SiO2 surface by femtosecond-laser-induced homogeneous nanostructure formation
Minami Edakubo, Lukas Janos Richter, Yuya Haraguchi, Hiroko Aruga-Katori, J?rgen Ihlemann, and Godai Miyaji
Optical Materials Express
Optica Publishing Group
It has been reported that periodic nanostructures with a period size of 200-330 nm can be formed on silicon suboxide (SiOx, x approximate to 1) with 800-nm, 100-fs laser pulses at a fluence much smaller than that needed for nanostructuring on glasses such as fused silica and borosilicate glass. We demonstrated that a homogeneous SiO2 nanostructure with a period of -240 nm can be produced using a two-step ablation process and heat treatment in air at 1000 degrees C for 144 hours. Optical microscopic images of the nanostructured surface illuminated by non-polarized visible light show that the transmittance increases as the reflectivity decreases.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
2022年10月01日, 研究論文（学術雑誌）, 共同, 12, 10, 2159-3930, DOI(公開)(r-map), 3982, 3989 - Observation of Topological Flat Bands in the Kagome Semiconductor Nb3Cl8
Zhenyu Sun, Hui Zhou, Cuixiang Wang, Shiv Kumar, Daiyu Geng, Shaosheng Yue, Xin Han, Yuya Haraguchi, Kenya Shimada, Peng Cheng, Lan Chen, Youguo Shi, Kehui Wu, Sheng Meng, Baojie Feng
Nano Letters
American Chemical Society
The destructive interference of wavefunctions in a kagome lattice can give rise to topological flat bands (TFBs) with a highly degenerate state of electrons. Recently, TFBs have been observed in several kagome metals, including Fe3Sn2, FeSn, CoSn, and YMn6Sn6. Nonetheless, kagome materials that are both exfoliable and semiconducting are lacking, which seriously hinders their device applications. Herein, we show that Nb3Cl8, which hosts a breathing kagome lattice, is gapped out because of the absence of inversion symmetry, while the TFBs survive because of the protection of the mirror reflection symmetry. By angle-resolved photoemission spectroscopy measurements and first-principles calculations, we directly observe the TFBs and a moderate band gap in Nb3Cl8. By mechanical exfoliation, we successfully obtain monolayer Nb3Cl8, which is stable under ambient conditions. In addition, our calculations show that monolayer Nb3Cl8 has a magnetic ground state, thus providing opportunities to study the interplay among geometry, topology, and magnetism.
2022年06月08日, 研究論文（学術雑誌）, 共同, 22, 11, 1530-6984, DOI(公開)(r-map), 4596, 4602 - Sinusoidal Magnetic Structure of Andalusite-type AlxFe2-xGeO5 with x = 0.09 and 0.15
Kazuo Kakimoto, Hiroto Ohta, Yuya Haraguchi, Masato Hagihala, Shuki Torii, Takashi Kamiyama, and Hiroko Aruga Katori
Journal of the Physical Society of Japan
Physical Society of Japan
Neutron diffraction experiments on polycrystalline andalusite-type AlxFe2-xGeO5 with x = 0.09 and 0.15 were performed. The magnetic Bragg peaks with the propagation vectors of kx=0.09 = (0, 0.150(1), 0) for the sample with x = 0.09 and kx=0.15 = (0, 0.141(1), 0) for the sample with x = 0.15 were observed, which means that an incommensurate magnetic order was realized for each sample. The calculation of the magnetic structure factors by the Pawley method and the analysis of the irreducible representations revealed that both samples have a magnetic structure in which the magnetic moments rotate in the crystallographic ab-plane with sinusoidal modulation along the b-axis. By the Luttinger-Tisza method, we determined the sign of the nearest-neighbor exchange interaction constants that reproduce the magnetic structures obtained by the irreducible representation analysis.
2022年05月15日, 研究論文（学術雑誌）, 共同, 91, 5, 0031-9015, DOI(公開)(r-map), 054707 - Magnetism of AlxFe2-xGeO5 with Andalusite Structure
Kazuo Kakimoto, Saki Takada, Hiroto Ohta, Yuya Haraguchi, Masato Hagihala, Shuki Torii, Takashi Kamiyama, Hiroyuki Mitamura, Masashi Tokunaga, Atsushi Hatakeyama, and Hiroko Aruga Katori
Journal of the Physical Society of Japan
The Physical Society of Japan
The magnetism of AlxFe2-xGeO5 from x = 0.09 to 0.91 with the andalusite structure was examined. AlxFe2-xGeO5 at low temperatures was found to show a weak ferromagnet-like behavior for x 0.3 and a spin glass behavior for x 0.3. The small spontaneous magnetization observed in the weak ferromagnet-like samples may be caused by the existence of Dzyaloshinsky-Moriya interaction and the difference in the magnitudes of the magnetic moments of Fe3+ in the octahedral and trigonal bipyramidal sites. The appearance of the spin glass behavior implies that the dilution of Fe ions by Al ions in AlxFe2-xGeO5 causes the competition between ferromagnetic and antiferromagnetic interactions. The x dependence of the site occupancy of Fe ions suggests that Fe2GeO5 with the andalusite structure cannot be synthesized.
2022年05月15日, 研究論文（学術雑誌）, 共同, 91, 5, 0031-9015, DOI(公開)(r-map), 054704-1, 054704-7 - Formation of the metastable iron(III) germanate Fe2GeO5 through kinetic control of the oxidative reaction
K. Kakimoto, Y. Ohki, S. Takada, Y. Haraguchi, A. Yamamoto, and H. Aruga Katori
Chemistry Letters
The Chemical Society of Japan
Synthesis of complex oxides requires high temperatures to overcome barriers due to the diffusion of solids. Therefore, the most stable polymorphs are obtained in general reactions. However, it is necessary to design kinetic reactions with low initial energy barriers and control the reaction path and products to synthesize novel and metastable oxides. We report the synthesis of a metastable Fe2GeO5 with a kyanite-type structure via kinetic control of oxidative reaction in Fe2GeO4. It is also found that Fe2GeO5 was not synthesized at all by the conventional method, high-pressure synthesis method, or coprecipitation method. Our result indicates that kinetic control of the oxidative reaction is a promising method for synthesizing metastable materials.
2022年04月, 研究論文（学術雑誌）, 共同, 51, 4, 0366-7022, DOI(公開)(r-map), 451, 454 - Magnetic properties of Eu(Co1-xNix)2P2
Raito Nakamura, Hiroto Ohta, Yoshio Kobayashi , Yuya Haraguchi, Hiroko Aruga Katori, and Jin Nakamura
Journal of the Physical Society of Japan
Physical Society of Japan
Solid solution 122-type compounds, Eu(Co1-xNix)(2)P-2, were investigated using crystallographic, magnetic, and Eu-151 Mossbauer effect measurements. A discontinuous isostructural phase transition from the uncollapsed tetragonal (ucT) to collapsed tetragonal (cT) structure was observed around x = 0.3. In the ucT region, Eu was divalent and showed helical magnetism of the Eu sublattice as well as at x = 0. However, in the cT region, Eu had an intermediate valence (+2.2 at 300 K) and showed paramagnetic behavior. The temperature dependence of the Eu valence was in good agreement with the Inter-Configurational Fluctuation (ICF) model. The Eu sublattice lost its magnetic order, but the Co/Ni sublattice exhibited itinerant ferromagnetism around 150 K. In addition, the net magnetization was lost due to the antiferromagnetic-like reorientation of the Co/Ni spins below 70 K. This magnetic structure was not observed in other 122-compounds and was a novel magnetic phase.
2022年02月15日, 研究論文（学術雑誌）, 共同, 91, 2, 0031-9015, DOI(公開)(r-map), 024701 - Spin-glass transition in the spin-orbit-entangled Jeff = 0 Mott insulating double-perovskite ruthenate
Hayato Yatsuzuka, Yuya Haraguchi, Akira Matsuo, Koichi Kindo & Hiroko Aruga Katori
Scientific Reports
Nature Portfolio
We have successfully synthesized new Ru4+ double perovskite oxides SrLaInRuO6 and SrLaGaRuO6, which are expected to be a spin-orbit coupled J(eff) = 0 Mott insulating ground state. Their magnetic susceptibility is much significant than that expected for a single Ru4+ ion for which exchange coupling with other ions is negligible. Their isothermal magnetization process suggests that there are about 20 percent isolated spins. These origins would be the Ru3+/Ru5+ magnetic defects, while the regular Ru4+ sites remain nonmagnetic. Moreover, SrLaGaRuO6 shows a spin-glass-like magnetic transition at low temperatures, probably caused by isolated spins. The observed spin-glass can be interpreted by the analogy of a dilute magnetic alloy, which can be seen as a precursor to the mobile J(eff) = 1 exciton as a dispersive mode as predicted.
2022年02月14日, 研究論文（学術雑誌）, 共同, 12, 1, 2045-2322, DOI(公開)(r-map), 2429 - Quantum paramagnetism in the hyperhoneycomb Kitaev magnet beta-ZnIrO3
Yuya Haraguchi, Arika Matsuo, Koichi Kindo, Hiroko Aruga Katori
Physical Review Materials
American Physical Society
A polycrystalline sample of the hyperhoneycomb iridate beta-ZnIrO3 was synthesized via a topochemical reaction, and its structural, magnetic, and thermodynamic properties were investigated. The magnetization and heat capacity data show the absence of long-range magnetic order at least down to 2 K. A positive Curie-Weiss temperature theta(w) similar to 45 K probed by the temperature dependence of magnetic susceptibility indicates that a Kitaev interaction is dominant. These observations suggest that a quantum spin liquid may have been realized. Furthermore, the observation of linear temperature-dependent contribution to the heat capacity with no magnetic field effect evidences gapless excitation. These facts are surprisingly contrary to the chemical disorder evidenced by the crystallographic analysis. By discussing the differences in the size effect of Z(2) fluxes in two-and three-dimensional Kitaev magnets, we propose that there is a hidden mechanism to protect the quantum spin liquid state from chemical disorder.
2022年02月07日, 研究論文（学術雑誌）, 共同, 6, 2, 2475-9953, DOI(公開)(r-map), L021401-1, L021401-6 - Quantum antiferromagnet bluebellite comprising a maple-leaf lattice made of spin-1/2 Cu2+ ions
Haraguchi, Yuya; Matsuo, Akira; Kindo, Koichi; Hiroi, Zenji
PHYSICAL REVIEW B
AMER PHYSICAL SOC
Spin-1/2 maple-leaf lattice antiferromagnets are expected to show interesting phenomena originating from frustration effects and quantum fluctuations. We report the hydrothermal synthesis of a powder sample of bluebellite Cu6IO3(OH)10Cl as a first potential candidate. Magnetization and heat capacity measurements reveal moderate frustration with a Curie-Weiss temperature of -35 K, and a magnetic transition at TN = 17 K. Surprisingly, the magnetic susceptibility and heat capacity above TN are well reproduced by the Bonner-Fisher model, which suggests that a one-dimensional spin correlation with a magnetic interaction of 25 K occurs in the apparently two-dimensional lattice. This emergent one-dimensionality cannot be explained by orbital ordering or dimensional reduction due to geometrical frustration. We believe that there is an unknown mechanism to cause one-dimensionality in the spin-1/2 maple-leaf lattice antiferromagnet.
2021年11月29日, 研究論文（学術雑誌）, 共同, 104, 17, 2469-9950, DOI(公開)(r-map), 174439-1, 174439-6 - Metallic state in the vicinity of molecular orbital crystallization in the d1 thiospinel ZnTi2S4 prepared via a reductive ion-exchange reaction
Haraguchi, Yuya; Arikai, Hiroki; Katori, Hiroko Aruga
JOURNAL OF PHYSICS-CONDENSED MATTER
IOP PUBLISHING LTD
A novel Ti3+-based thiospinel ZnTi2S4 is successfully synthesized via a low-temperature ion-exchange reaction. ZnTi2S4 shows a signature of metallic ground state evidenced by a contribution of conduction electrons in the heat capacity and Pauli-like paramagnetic susceptibility. These observations contrast to the electronic state of similar Ti3+-based spinel MgTi2O4 exhibiting the metal-insulator transition associated with a molecular orbital crystallization (MOC). Furthermore, the magnetic susceptibility of ZnTi2S4 shows a pseudogap-like behavior indicated by a vast peak in the magnetic susceptibility around 110 K, likely originating from the MOC fluctuation. The origin of the difference in the electronic states of MgTi2O4 and ZnTi2S4 would be due to the different magnitude of overlap between Ti 3d and p orbitals (O: 2p and S: 3p). The presence of a MOC state in the close vicinity of insulator-metal transition may suggest the importance of itinerancy in a MOC.
2021年09月29日, 研究論文（学術雑誌）, 共同, 33, 39, 0953-8984, DOI(公開)(r-map), 395603 - 4d3 Ru5+ triangular lattice antiferromagnets: Layered rock-salt beta-Li3Mg2RuO6 and ion-exchanged delafossite Ag3Mg2RuO6
Haraguchi, Yuya; Kakimoto, Kazuo; Katori, Hiroko Aruga
JOURNAL OF SOLID STATE CHEMISTRY
ACADEMIC PRESS INC ELSEVIER SCIENCE
Y The crystal structure and magnetic properties of Ru5+ triangular lattice antiferromagnets beta-Li3Mg2RuO6 and Ag3Mg2RuO6 are reported. We successfully synthesized a pseudohexagonal layered rock-salt type phase beta-Li3Mg2RuO6 with 2:1 ordering of Mg and Ru, which is a polymorph of an orthorhombic partial ordered rock-salt phase alpha-Li3Mg2RuO6. Shortening a calcinating time and adding excessive amounts of Li can prevent a polymorphic transformation from beta-Li3Mg2RuO6 to alpha-Li3Mg2RuO6. An ordered delafossite compound Ag3Mg2RuO6 has been obtained by topochemical molten salt ionic exchange reaction to beta-Li3Mg2RuO6. In beta-Li3Mg2RuO6 and Ag3Mg2RuO6, multiple superexchange pathways Ru5+-O2--O2--Ru5+ leads to large antiferromagnetic interactions of theta(W) = -113.9 and -108.1 K, respectively, despite a long distance between the magnetic Ru5+ ions. In addition, beta-Li3Mg2RuO6 and Ag3Mg2RuO6 exhibit antiferromagnetic orderings with a trace of spin glasslike contribution at T-N = 13 and 24 K, respectively, which is evidenced by the heat capacity measurement. While beta-Li3Mg2RuO6 exhibits a magnetic behavior that follows the Curie-Weiss curve up to just above T-N, Ag3Mg2RuO6 exhibits a magnetic behavior that deviates from the Curie-Weiss curve below 100 K, which is considerably higher than T-N. The different magnetic behaviors suggest a difference in magnetic dimensionality, indicating that the difference in the coordination environment around interlayer between Li+ and Ag+ ions gives rise to considerably different interlayer superexchange pathways in both systems.
2021年07月, 研究論文（学術雑誌）, 共同, 299, 0022-4596, DOI(公開)(r-map), 122171-1, 122171-6 - Strong antiferromagnetic interaction owing to a large trigonal distortion in the spin-orbit-coupled honeycomb lattice iridate CdIrO3
Yuya Haraguchi, and Hiroko Aruga Katori
Physical Review Materials
American Physical Society.
2020年04月03日, 研究論文（学術雑誌）, 共同, 4, 4, DOI(公開)(r-map), 044401-1, 044401-5 - Frustrated magnetism in the J1-J2 honeycomb lattice compounds MgMnO3 and ZnMnO3 synthesized via a metathesis reaction
Haraguchi, Yuya; Nawa, Kazuhiro; Michioka, Chishiro; Ueda, Hiroaki; Matsuo, Akira; Kindo, Koichi; Avdeev, Maxim; Sato, Taku J.; Yoshimura, Kazuyoshi
PHYSICAL REVIEW MATERIALS
AMER PHYSICAL SOC
We investigated the magnetic properties of the ilmenite-type manganates MgMnO3 and ZnMnO3, both of which are composed of a honeycomb lattice of magnetic Mn4+ ions. Both compounds show antiferromagnetic order with weak ferromagnetic moments. In particular, MgMnO3 exhibits a magnetization reversal behavior which can be described by the N-type ferrimagnetism in the Neel's classification. The relationship between the magnetic properties and the crystal and magnetic structures probed by the neutron diffraction experiments indicates that the two honeycomb lattice magnets have different J(1)-J(2) parameter sets, placing them in the distinct regions in the phase diagram; both nearest neighbor (NN) and next nearest neighbor (NNN) exchange interactions are antiferromagnetic in MgMnO3, while NN and NNN interactions become ferromagnetic and antiferromagnet, respectively, in ZnMnO3.
2019年12月17日, 研究論文（学術雑誌）, 共同, 3, 12, 2475-9953, DOI(公開)(r-map) - Frustrated magnetism of the maple-leaf-lattice antiferromagnet MgMn3O7 3H2O
Haraguchi, Yuya; Matsuo, Akira; Kindo, Koichi; Hiroi, Zenji
PHYSICAL REVIEW B
AMER PHYSICAL SOC
We present the novel hydrated layered manganate MgMn3O7 center dot 3H(2)O as a maple-leaf-lattice (MLL) antiferromagnet candidate. The MLL is obtained by regularly depleting 1/7 of the lattice points from a triangular lattice so that the magnetic connectivity z = 5 and is thus intermediately frustrated between the triangular (z = 6) and kagome (z = 4) lattices. In MgMn3O7 center dot 3H(2)O, the Mn4+ ions carrying Heisenberg spin 3/2 form a regular MLL lattice in the quasi-two-dimensional structure. Magnetization and heat capacity measurements using a hydrothermally prepared powder sample reveal successive antiferromagnetic transitions at 5 and 15 K. A high-field magnetization curve up to 60 Tat 1.3 K exhibits a multistep plateaulike anomaly. We discuss the unique frustration of the MLL antiferromagnet in which the chiral degree of freedom may play an important role.
2018年08月13日, 研究論文（学術雑誌）, 共同, 98, 064412, 2469-9950, DOI(公開)(r-map) - Magnetic ordering with an XY-like anisotropy in the honeycomb lattice iridates ZnIrO3 and MgIrO3 synthesized via a metathesis reaction
Haraguchi, Yuya; Michioka, Chishiro; Matsuo, Akira; Kindo, Koichi; Ueda, Hiroaki; Yoshimura, Kazuyoshi
PHYSICAL REVIEW MATERIALS
AMER PHYSICAL SOC
We have successfully synthesized the novel antiferromagnets with Ir4+ honeycomb lattice ZnIrO3 and MgIrO3 and investigated their magnetic and thermodynamic properties. The two iridates are isomorphic but exhibit qualitatively different magnetic properties. ZnIrO3 shows antiferromagnetic ordering below 46.6 K, whereas MgIrO3 displays weak ferromagnetic behavior below 31.8 K, owing to formation of a canted antiferromagnetic ordering. The measurement of magnetic susceptibility with using an oriented powder sample revealed the presence of an XY-like magnetic anisotropy and a tilting magnetic structure which is possibly stabilized by the Kitaev interaction. Moreover, magnetization curves of ZnIrO3 and MgIrO3 up to 60 T show different behaviors, demonstrating that each magnetic ground state is different with each other. We discuss the difference in the ground state between ZnIrO3 and MgIrO3 from the viewpoint a magnetic model consisting of the Kitaev and Dzyaloshinskii-Moriya interactions with the spin-frustration effect on the honeycomb lattice.
2018年05月18日, 研究論文（学術雑誌）, 共同, 2, 054411, 2475-9953, DOI(公開)(r-map) - Highly Spin-frustrated Magnetism in the Topochemically Prepared Triangular Lattice Cluster Magnets Na3A2(MoO4)2Mo3O8 (A = In, Sc)
Yuya Haraguchi, Chishiro Michioka, Hiroaki Ueda, and Kazuyoshi Yoshimura
Chemistry - A European Journal
Wiley VCH Verlag GmbH and Co
2017年10月09日, 研究論文（学術雑誌）, 共同, 23, DOI(公開)(r-map), 15879, 15883 - Magnetic-nonmagnetic Phase Transition with Interlayer Charge Disproportionation of Nb3 Trimers in the Cluster Compound Nb3Cl8
Yuya Haraguchi, Chishiro Michioka, Manabu Ishikawa, Yoshiaki Nakano, Hideki Yamochi, Hiroaki Ueda, and Kazuyoshi Yoshimura
Inorganic Chemistry
American Chemical Society
2017年02月27日, 研究論文（学術雑誌）, 共同, 56, 6, DOI(公開)(r-map), 3483, 3488 - Tetramer spin singlet instability in the fluorine-substituted pyrochlore superconducting system Cd2Re2O7-xFx
Yuya Haraguchi, Chishiro Michioka, Hiroaki Ueda, and Kazuyoshi Yoshimura
Journal of Physics: Condensed Matter
IOP Publishing Ltd
2016年07月06日, 研究論文（学術雑誌）, 共同, 28, 355602, DOI(公開)(r-map) - Spin-liquid behavior in the spin-frustrated Mo3 cluster magnet Li2ScMo3O8 in contrast to magnetic ordering in isomorphic Li2InMo3O8
Yuya Haraguchi, Chishiro Michioka, Masaki Imai, Hiroaki Ueda, and Kazuyoshi Yoshimura
Physical Review B
2015年07月09日, 研究論文（学術雑誌）, 共同, 92, 014409, DOI(公開)(r-map) - Unconventional multicritical point in the S = 1/2 Re2-cluster magnet La3Re2O10
Yuya Haraguchi, Chishiro Michioka, Hiroaki Ueda, and Kazuyoshi Yoshimura
Physical Review B
American Physical Society
2014年08月05日, 研究論文（学術雑誌）, 共同, 90, 064403, DOI(公開)(r-map)
研究発表、招待講演等
- クラスターモット絶縁体の量子スピン液体再考
物性研究所短期研究会「新物質開発・システム創成研究の最前線：分子・クラスターがもたらす物性と機能」
2024年10月04日, 口頭発表（招待・特別） - 低温トポケミカル反応と第一原理計算を組み合わせた量子磁性体の合成反応設計
第31回みちのく磁性談話会
2024年06月22日, 口頭発表（招待・特別） - 準安定結晶相からの量子物性の創出と課題
第18回 未来材料セミナー
2024年04月05日, 公開講演，セミナー，チュートリアル，講習，講義等 - 新しいキタエフ物質の開発
日本物理学会 2023年春季大会
2024年03月19日, 口頭発表（招待・特別） - 分子性ユニットを含む量子磁性体の水熱合成
学術変革領域研究(A)超セラミックス 公開シンポジウム
2024年01月24日, シンポジウム・ワークショップ パネル（指名） - 速度論的反応設計に基づくキタエフ磁性体の開発
結晶育成と電子物性に関する研究会
2023年10月31日, 口頭発表（招待・特別） - 122型鉄系化合物KFe2P2における近藤効果
日本物理学会第78回年次大会
2023年09月18日, ポスター発表 - Co2+ハニカム格子量子磁性体の合成とKitaev磁性
日本物理学会第78回年次大会
2023年09月18日, ポスター発表 - S=1 Ni2+ ハニカム格子物質ANi2TeO6はキタエフ磁性体か?
日本物理学会第78回年次大会
2023年09月18日, 口頭発表（一般） - 新しいダイヤモンド格子フラストレート磁性体における渦磁性の探索
日本物理学会第78回年次大会
2023年09月16日, ポスター発表 - ブリージング格子を有する磁性体における新奇フラストレート磁性の開拓
日本物理学会第78回年次大会
2023年09月16日, ポスター発表 - 高スピンd7 Co2+ Jeff=1/2 完全カゴメ磁性体の水熱合成
日本物理学会 2023年春季大会
2023年03月23日, 口頭発表（一般） - 固体化学の立場から見えてきたキタエフ磁性体の開発指針
第32回日本MRS年次大会
2022年12月06日, 口頭発表（招待・特別） - 高スピンd7キタエフ磁性体CaCo2TeO6の磁気異方性評価
日本物理学会2022年秋季大会
2022年09月13日, 口頭発表（一般） - 低温固相メタセシスによって合成した四面体配位d8系スピン軌道結合J=0磁性候補物質NiRh2O4における磁気秩序の観測
日本物理学会2022年秋季大会
2022年09月13日, 口頭発表（一般） - 過剰アルカリ金属インターカレート系Mo3クラスターMott絶縁体における創発的三角格子磁性
日本物理学会2022年秋季大会
2022年09月12日, 口頭発表（一般） - 新規キタエフ模型候補物質CaCo2TeO6の中性子回折
日本物理学会2022年秋季大会
2022年09月12日, 口頭発表（一般） - Frustrated magnetism in alkaline-intercalated Mo3O8-type compounds
29th International Conference on Low Temperature Physics
2022年08月23日, ポスター発表 - Kitaev spin liquid signature in the hyperhoneycomb iridate
29th International Conference on Low Temperature Physics
2022年08月22日, ポスター発表 - 新しいS = 1カゴメ格子ニッケル化合物の磁化プラトー
日本物理学会 第77回年次大会（2022年）
2022年03月15日, 口頭発表（一般） - From rocksalt to ilmenite: a metathesis route for the synthesis of novel quantum materials
Pacifichem 2021
2021年12月17日, 口頭発表（一般） - 中間原子価化合物Eu(Co1-xNix)2P2の151Euメスバウアー分光測定によるEu価数の研究
日本物理学会2021年秋季大会
2021年09月23日, ポスター発表 - ハイパーハニカム格子を有するKitaev常磁性体β-ZnIrO3の磁気状態の再考および周辺物質の探索
日本物理学会2021年秋季大会
2021年09月22日, 口頭発表（一般） - kyanite構造Fe2GeO5の磁性
日本物理学会2021年秋季大会
2021年09月22日, 口頭発表（一般） - ハニカム格子系Jeff = 0スピン軌道結合磁性体候補物質CdRuO3
日本物理学会2021年秋季大会
2021年09月21日, 口頭発表（一般） - 高スピンd7電子系Kitaev-Heisenberg模型カゴメ格子反強磁性体BaCo3(XO4)2(OH)2 (X = V, As)の合成と磁性
日本物理学会2021年秋季大会
2021年09月21日, ポスター発表 - ハニカム格子を持つイリジウム酸化物のトポケミカル合成の最近の動向
日本物理学会2021年秋季大会
2021年09月20日, ポスター発表 - 低温固相メタセシスによるサイトミクスチャーの無いスピネル酸化物MgCo2O4の合成
粉体粉末冶金協会2021年度春季大会
2021年06月07日, 口頭発表（一般） - S=1/2二次元メイプルリーフ格子反磁性体Bluebelliteにおける創発的一次元磁性
日本物理学会第76回年次大会
2021年03月15日, 口頭発表（一般） - 新しいKitaev-Heisenberg磁性体CaCo2TeO6における磁場誘起スピン液体の可能性
日本物理学会第76回年次大会
2021年03月15日, 口頭発表（一般） - イルメナイト型ルテネイトMgRuO3におけるスピン軌道結合金属の可能性
日本物理学会第76回年次大会
2021年03月13日, 口頭発表（一般） - Jeff = 0スピン軌道結合磁性候補物質SrLaGaRuO6におけるスピングラス転移
日本物理学会第76回年次大会
2021年03月13日, 口頭発表（一般） - andalusite構造AlxFe2-xGeO5(x = 0.15, 0.2)の磁気構造研究
日本物理学会第76回年次大会
2021年03月12日, 口頭発表（一般） - 中間原子価化合物Eu(Co1-xNix)2P2の構造と磁性
日本物理学会第76回年次大会
2021年03月12日, 口頭発表（一般） - 低温合成による新しいキタエフ物質の探索
第135回フロンティア材料研究所講演会
2021年01月21日, 口頭発表（招待・特別） - トポケミカル安定化されたハニカム格子イリジウム酸化物の物性
日本物理学会2020年秋季大会
2020年09月10日, 口頭発表（一般） - イルメナイト構造をもつスピン軌道結合イリジウム酸化物における結晶構造と磁性の関係
日本物理学会第75回年次大会
2020年03月17日, 口頭発表（一般） - 低温複分解反応を用いた新規キタエフ候補物質の探索
日本物理学会2019年秋季大会
2019年09月10日, ポスター発表 - 新しいハイパーハニカム格子イリジウム酸化物の合成と物性
日本物理学会第74回年次大会
2019年03月16日, 口頭発表（一般）