| Project/Area Number |
18K03537
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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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| Review Section |
Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
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| Research Institution | Shizuoka University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
松田 康弘 東京大学, 物性研究所, 准教授 (10292757)
関山 明 大阪大学, 基礎工学研究科, 教授 (40294160)
徳永 将史 東京大学, 物性研究所, 准教授 (50300885)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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| Keywords | 重い電子系 / 強相関電子系 / メタ磁性 / 強磁場 / 比熱 / 純良単結晶 / 電子状態 |
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| Outline of Final Research Achievements |
Exotic properties like unconventional superconductivity or non-Fermi-liquid state appear near the quantum critical point (QCP) at which the RKK and the Kondo interactions balance. Some non-magnetic heavy fermion system near QCP shows metamagnetism whose mechanism may relate the mechanism emerging unconventional superconductivity. Thus, it is worth to clarify the mechanism of metamagnetism in non-magnetic heavy fermion system and determine the electronic states at metamagnetism.
We observed temperature dependence of magnetic susceptibility and the low temperature specific heat at high magnetic field in high quality single crystal of YbNi2Ge2. The magnetic field dependence of Sommerfeld coefficient shows monotonical increase as magnetic field increases up to 14 T, which corresponds to the field dependence of magnetic susceptibility. The relation between field dependences of Sommerfeld coefficient and magnetic susceptibility is well explained by the thermodynamic Maxwell’s relation.
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| Academic Significance and Societal Importance of the Research Achievements |
YbNi2Ge2の高純度試料を得ることに成功し、磁場中の比熱測定を通じて電子比熱係数が磁場依存性を持つことを明らかにした。電子比熱係数は、14テスラまで単調増大傾向を示す磁場依存性をもち、電子比熱係数と磁化率の磁場依存性を結ぶマックスウェルの関係式と呼ばれる熱力学的関係式でよく説明ができることが明らかになった。この結果、メタ磁性転移磁場である40テスラ近傍で比熱測定を行うための基礎的情報が得られ、新奇超伝導体のメカニズム解明にもつながると期待される、非磁性の重い電子系におけるメタ磁性メカニズム解明への足掛かりを得た。
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