2022 Fiscal Year Final Research Report
Theoretical study and materials search on gigantic negative thermal expansion phenomena in correlated electron systems
Project/Area Number |
19K21858
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Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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Allocation Type | Multi-year Fund |
Review Section |
Medium-sized Section 13:Condensed matter physics and related fields
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Research Institution | Waseda University |
Principal Investigator |
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Co-Investigator(Kenkyū-buntansha) |
勝藤 拓郎 早稲田大学, 理工学術院, 教授 (00272386)
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Project Period (FY) |
2019-06-28 – 2023-03-31
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Keywords | 負熱膨張現象 / ハニカム格子反強磁性体 / 交換相互作用 / 磁気体積効果 / 磁気相転移 / 逆ペロフスカイト型マンガン窒化物 / スピン-格子結合 / 反強磁性秩序 |
Outline of Final Research Achievements |
We theoretically designed a guide for material search for magnetism-induced negative thermal expansion (NTE) materials, which induce crystal volume expansion due to magnetic phase transition with lowering temperature and aimed to discover new NTE materials in collaboration with material synthesis. We have theoretically predicted the occurrence of giant NTE phenomena associated with antiferromagnetic ordering in transition metal honeycomb-lattice compounds consisting of edge-shared MX6 octahedra, where M and X are a transition metal ion and a ligand ion, respectively. We have also clarified the universal physical origin of the magnetism-induced NTE. Based on the material design guidelines clarified here, we searched the database of honeycomb-lattice antiferromagnets and found a new NTE material that actually exhibits NTE associated with a magnetic phase transition to antiferromagnetic order.
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Free Research Field |
理論物性物理学
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Academic Significance and Societal Importance of the Research Achievements |
温度降下に伴い結晶体積が膨張する負熱膨張物質と、通常の(温度降下により結晶体積が収縮する)物質とを複合させると、それぞれの体積膨張と収縮が相殺し、温度が変わっても体積や長さが変化しにくい材料を作ることができる。昨今、ますます精緻化してきている光学素子、計測機器、精密機械の製造において、このような材料への要請が高まっていおり、精力的にその研究が進められている。本研究では、磁気転移に伴う負熱膨張現象の物質設計・探索の新しく普遍的な指針を示し、それに従って新しい負熱膨張を見出した。このことは、これまで研究者の経験と勘に頼らざるを得なかった負熱膨張物質の探索に革新的な寄与をもたらすと期待される。
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