構造安定化予測に基づく新規機能性酸化物の創製

• Project Area: Exploration of nanostructure-property relationships for materials innovation
• Project/Area Number: 16H00888
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering
• Research Institution: Kyoto University
• Principal Investigator: 島川 祐一 京都大学, 化学研究所, 教授 (20372550)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000); Fiscal Year 2017: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000); Fiscal Year 2016: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
• Keywords: イオン結晶 / 強相関電子系 / 構造・機能材料

Outline of Annual Research Achievements

本研究では、イオン結晶としての遷移金属酸化物を対象として、イオン結合に基づく構造安定性の観点からの新物質探索と合成を行なってきた。
その中で、サイト間電荷移動に伴う格子変化について、イオンモデルにより構造安定化予測を行ったところ、LaCu3Fe4O12で見出された負の熱膨張もLaCu3Cr4O12で見出された正の熱膨張も定量的に説明できることが明らかになった。この結果は、イオンモデルに基づく価数変化とサイズ効果が、サイト間電荷移動による構造変化の主要な要因であることを示している、また、この成功は、負の熱膨張を含めた機能特性物質の設計がイオンモデルに基づいて可能であることを示すものである。（この成果に関する論文を投稿準備中）一連の成果は、「イオン半径」というインフォマティックスの観点からも興味深い。
また、高圧法を用いて、異常原子価状態Feイオンを含んだCa0.5Bi0.5FeO3を合成し、この物質が電荷不均化とサイト間電荷移動の逐次相転移を示すことを明らかにしたが、同様の手法により合成したSr0.5Bi0.5FeO3では異常高原子価Fe3.5+イオンが結晶の<111>方向に沿って3:1のFe3+とFe5+に秩序配列する単一の電荷不均化転移のみを示すことが明らかとなった。これは、Ca0.5Bi0.5FeO3での逐次相転移とは大きく異なる様式で異常高原子価状態の電子的な不安定性を解消していることを示しており、ペロブスカイト構造のAサイトにおけるイオンサイズの違いによる化学圧力が、Biイオンの電荷移動に大きく影響を与えることを示している。
イオンモデルは、固体物質に対して古くからある最も基本的な考え方ではあるが、多くの物性変化の説明に極めて有用である。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] University of Edinburgh/ISIS Neutron Facility(英国)
• [Int'l Joint Research] エジンバラ大学/ラザフォードアップルトン研究所(英国)
• [Int'l Joint Research] モンペリエ大学(フランス)
• [Int'l Joint Research] オハイオ州立大学/カリフォルニア大学(米国)
• [Journal Article] Charge Disproportionation in Sr0.5Bi0.5FeO3 Containing Unusually High Valence Fe3.5+ (2018)
  • Author(s): P. Xiong, F. D. Romero, Y, Hosaka, H. Guo, T. Saito, W. -T. Chen, Y. -C. Chuang, H. -S. Sheu, G. McNally, J. P. Attfield, and Y. Shimakawa
  • Journal Title: Inorg. Chem. Volume: 57 Issue: 2 Pages: 843-848
  • DOI: 10.1021/acs.inorgchem.7b02785
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Charge and spin order in Ca0.5Bi0.5FeO3: Idle spins in the charge disproportionated state (2017)
  • Author(s): F. D. Romero, Y. Hosaka, N. Ichikawa, T. Saito, G. McNally, J. P. Attfield, and Y. Shimakawa
  • Journal Title: Phys. Rev. B Volume: 96 Issue: 6 Pages: 064434-064434
  • DOI: 10.1103/physrevb.96.064434
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Successive Charge Transitions of Unusually High-Valence Fe3.5+: Charge Disproportionation and Intermetallic Charge Transfer (2017)
  • Author(s): Y. Hosaka, F. D. Romero, N. Ichikawa, T. Saito, and Y. Shimakawa
  • Journal Title: Angew. Chem. Int. Ed. Volume: 56 Issue: 15 Pages: 4243-4246
  • DOI: 10.1002/anie.201700881
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Two Charge Ordering Patterns in the Topochemically Synthesized Layer-Structured Perovskite LaCa2Fe3O9 with Unusually High Valence Fe3.67+ (2017)
  • Author(s): H. Guo, Y. Hosaka, F. D. Romero, T. Saito, N. Ichikawa, and Y. Shimakawa
  • Journal Title: Inorg. Chem. Volume: 56 Issue: 6 Pages: 3695-3701
  • DOI: 10.1021/acs.inorgchem.7b00104
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] G-type antiferromagnetic order in the metallic oxide LaCu3Cr4O12 (2017)
  • Author(s): T Saito, S. Zhang, D. Khalyavin, P. Manuel, J. P. Attfield, and Y. Shimakawa
  • Journal Title: Phys. Rev. B (Rapid) Volume: 95 Issue: 4 Pages: 041109-041109
  • DOI: 10.1103/physrevb.95.041109
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Crystal structures at atomic resolution of the perovskite-related GdBaMnFeO5 and its oxidized GdBaMnFeO6 (2017)
  • Author(s): S. Garcia-Martin, K. Manabe, E. Urones-Garrote, D. Avila-Brande, N. Ichikawa, and Y. Shimakawa
  • Journal Title: Inorg. Chem. Volume: 56 Issue: 3 Pages: 1412-1217
  • DOI: 10.1021/acs.inorgchem.6b02472
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] 2:1 Charge disproportionation in perovskite-structure oxide La1/3Ca2/3FeO3 with unusually-high-valence Fe3.67+ (2017)
  • Author(s): H. Guo, Y. Hosaka, H. Seki, T. Saito, N. Ichikawa, and Y. Shimakawa
  • Journal Title: J. Solid State Chem. Volume: 246 Pages: 199-202
  • DOI: 10.1016/j.jssc.2016.11.027
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Charge and spin order in the perovskite CaFe0.5Mn0.5O3: Charge disproportionation behavior of randomly arranged Fe4+ (2016)
  • Author(s): H. Hosaka, N. Ichikawa, T. Saito, J. P. Attfield, and Y. Shimakawa
  • Journal Title: Phys. Rev., B Volume: 94 Issue: 10 Pages: 104429-104429
  • DOI: 10.1103/physrevb.94.104429
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Geometrical Spin Frustration of Unusually High Valence Fe5+ in the Double Perovskite La2LiFeO6 (2016)
  • Author(s): P. Xiong, H. Seki, H. Guo, Y. Hosaka, T. Saito, M. Mizumaki, and Y. Shimakawa
  • Journal Title: Inorg. Chem. Volume: 56 Issue: 12 Pages: 6218-6222
  • DOI: 10.1021/acs.inorgchem.6b00827
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] Charge and spin order in oxides containing unusually high-valence cations (2017)
  • Author(s): Y. Shimakawa
  • Organizer: Core-to-Core Workshop "Novel Quantum and Functional Materials -Design and Synthesis-"
  • Int'l Joint Research / Invited
• [Presentation] Control of Oxygen Coordination Environment in Transition-Metal Oxides (2017)
  • Author(s): Y. Shimakawa
  • Organizer: International Workshop on Oxide Electronics (WOE24)
  • Int'l Joint Research / Invited
• [Presentation] Charge ordering patterns in A-site ordered/disordered triple perovskites with unusually high valence Fe3.67+ (2017)
  • Author(s): H. Guo, Y. Hosaka, T. Saito, N. Ichikawa, and Y. Shimakawa
  • Organizer: International Conference on Powder and Powder Metallurgy (JSPMIC 2017)
  • Int'l Joint Research
• [Presentation] High pressure synthesis and the physical properties of Sr0.5-xCaxBi0.5FeO3 (2017)
  • Author(s): P. Xiong, F. D. Romero, Y. Hosaka, H. Guo, T. Saito, and Y. Shimakawa
  • Organizer: International Conference on Powder and Powder Metallurgy (JSPMIC 2017)
  • Int'l Joint Research
• [Presentation] Unusual charge and spin transitions in perovskite-structure oxides containing unusually high-valence iron (2017)
  • Author(s): Y. Shimakawa
  • Organizer: The 6th Toyota RIKEN International Workshop
  • Int'l Joint Research
• [Presentation] 異常高原子価Feイオンが示す特異な電荷転移現象 (2017)
  • Author(s): 島川 祐一
  • Organizer: 第2回固体化学フォーラム研究会
  • Invited
• [Presentation] Charge order in perovskite-structure Fe oxides (2016)
  • Author(s): Y. Shimakawa
  • Organizer: International Symposium on Solid State Chemistry
  • Place of Presentation: Bangalore, India
  • Year and Date: 2016-12-02
  • Int'l Joint Research / Invited
• [Presentation] High pressure in transition-metal oxides research: Materials synthesis and property control (2016)
  • Author(s): Y. Shimakawa
  • Organizer: E-MRS Fall meeting
  • Place of Presentation: Warsaw, Poland
  • Year and Date: 2016-09-20
  • Int'l Joint Research / Invited
• [Presentation] Novel transition-metal oxides with unusual valence cations (2016)
  • Author(s): Y. Shimakawa
  • Organizer: Symposium on Quantum Materials Synthesis: Grand Challenges and Opportunities
  • Place of Presentation: New York, USA
  • Year and Date: 2016-08-31
  • Int'l Joint Research / Invited
• [Presentation] Control of physical properties by cation order in perovskite-structure transition-metal oxides (2016)
  • Author(s): Y. Shimakawa
  • Organizer: 4th Workshop on Complex Oxides
  • Place of Presentation: Porquerolles, France
  • Year and Date: 2016-06-16
  • Int'l Joint Research / Invited
• [Presentation] Crystal and Magnetic Structures of Cation Ordered Perovskites with Unusual High Valence Iron (2016)
  • Author(s): Y. Shimakawa
  • Organizer: Rare Earth 2016
  • Place of Presentation: Sapporo, Japan
  • Year and Date: 2016-06-07
  • Int'l Joint Research / Invited
• [Remarks] 京都大学化学研究所、先端無機固体化学（島川）研究室
  • URL: http://www.scl.kyoto-u.ac.jp/~shimakgr/index.html
• [Remarks] Shimakawa group, ICR, Kyoto Univ
  • URL: http://www.scl.kyoto-u.ac.jp/~shimakgr/indexE.html
• [Remarks] 京都大学化学研究所、島川研究室
  • URL: http://www.scl.kyoto-u.ac.jp/~shimakgr/index.html