| Project/Area Number |
15KK0165
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| Research Category |
Fund for the Promotion of Joint International Research (Fostering Joint International Research)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Condensed matter physics II
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| Research Institution | Ibaraki University (2018-2019)
Osaka University (2015-2017) |
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Principal Investigator |
Nakano Takehito 茨城大学, 理工学研究科(理学野), 准教授 (50362611)
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| Project Period (FY) |
2016 – 2019
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥13,780,000 (Direct Cost: ¥10,600,000、Indirect Cost: ¥3,180,000)
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| Keywords | ゼオライト / アルカリ金属 / ナノクラスター / s電子 / 強磁性 / 中性子回折 / 高圧 |
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| Outline of Final Research Achievements |
Alkali-metal nanoclusters arrayed in zeolite crystals show various magnetic orderings such as ferro-, antiferro- and ferrimagnetism. In order to investigate the mechanism in detail, we studied these materials using neutron diffraction, muon spin relaxation (muSR) and so on, mainly in Rutherford-Appleton Lab. in the UK. We found that Na-K alloy clusters in LSX zeolite show an enormous enhancement of ferrimagnetism by applying pressure using He gas. We obtained a complete phase diagram by changing the pressure and the temperature. We performed muSR measurements under the high pressure and succeeded in observing the internal magnetic field indicating the bulk magnetism. For the ambient pressure phases of ferro- and ferrimagnetic samples, we performed polarized neutron diffraction measurements. We obtained the information about the spin density distribution in the nanoclusters for the first time.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究の対象物質には，遷移金属元素のd電子や希土類元素のf電子が全く含まれていない．本来，磁気秩序とは最も縁遠いと考えられるｓ電子が磁気秩序を示すという点で非常にユニークであると言える．本研究の成果は，周期的なナノ空間においてｓ電子がいかに強磁性を示すのかを解明する直接的な手がかりを得た点に学術的意義がある．
また，対象物質の構成元素はNa, K, Al, Si, O であり，地球上に極めてありふれた元素（ユビキタス元素）のみである．希少元素を全く用いずに磁性体を実現する指針を与えており，将来社会への還元も期待できる．
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