2018 Fiscal Year Final Research Report
Development of the spin frustration due to dynamical spin equilibrium and its induced successive magnetic phase transitions
| Project/Area Number |
16K05421
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Toyota Physical and Chemical Research Institute |
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Principal Investigator |
Kojima Norimichi 公益財団法人豊田理化学研究所, フェロー事業部門, フェロー (60149656)
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| Co-Investigator(Kenkyū-buntansha) |
岡澤 厚 東京大学, 大学院総合文化研究科, 助教 (30568275)
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| Research Collaborator |
Enomoto Masaya
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 集積型金属錯体 / スピンクロスオーバー / 動的スピン平衡 / メスバウアー分光 / スピンフラストレーション / 逐次相転移 / 連鎖物性 |
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| Outline of Final Research Achievements |
We have synthesized (C6H5)4P[Zn(II)Fe(III)(mto)3](mto = C2O3S) consisting of Fe(III)O3S3 and Zn(II)O6 octahedra and investigated the spin state of the Fe(III) site. ESR and 57Fe Mossbauer spectra revealed that the rapid spin equilibrium in which the high spin state and the low spin state exchange in the time scale of 0.1 ns < τ < 0.1 μs occurs at the Fe(III) site. In the case of (C6H5)4P[Mn(II)Fe(III)(mto)3], there exists a rapid spin equilibrium (τ < 0.1 μs) between the high-spin and low-spin states at the Fe(III) site, which induces the frustration of internal magnetic field between the ferromagnetic and antiferromagnetic interactions at the Mn(II) site. Owing to the frustration of internal magnetic field at the Mn(II) site due to the rapid spin equilibrium at the Fe(III) site, (C6H5)4P[Mn(II)Fe(III)(mto)3] undergoes the successive magnetic phase transitions at 30 K and 23 K. At 30 K, only Mn(II) spin is ordered, while both of the Mn(II) and Fe(III) spins are ordered at 23 K.
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| Free Research Field |
物性化学
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| Academic Significance and Societal Importance of the Research Achievements |
A[Mn(II)Fe(III)(C2O3S)3] (A = cation)において、Fe(III)の動的スピン平衡現象を媒介とした磁性金属イオン間磁気相互作用のフラストレーションが生まれる。A = (C6H5)4Pにおいては、Fe(III)の低スピン状態とMn(II)スピンの間には強磁性相互作用が発現するが、Fe(III)の高スピン状態とMn(II)スピンの間には反強磁性相互作用が発現する。このような動的スピン平衡と連鎖する磁気相互作用のフラストレーションが磁気相転移に与える影響は全く未知の分野であり、分子磁性のみならず広く物性科学に波及効果をもたらすものである。
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