| Project/Area Number |
16K05441
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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 | University of Toyama |
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Principal Investigator |
Kuwai Tomohiko 富山大学, 学術研究部理学系, 教授 (10251878)
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2016: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
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| Keywords | 熱電能 / 強相関電子系 / 比熱 / 極低温 / 装置開発 / 物質探索 / 多極子 / 1-2-20系 / 非フェルミ液体 / 1-2-2-18系 / 電子相関 / 磁気断熱消磁冷凍 / 純良大型単結晶 / La希釈系 |
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| Outline of Final Research Achievements |
In the early stage of the research, I constructed a measurement system of thermo-power (TEP) and specific heat (HC) at low temperatures (LT). I installed an ADR option of a commercial PPMS (Quantum Design) which already worked at the laboratory, and equipped them with hand-made devices which enable to measure TEP and HC down to 90 mK. Thanks to this installation, I succeeded to save a lot of time and money for my measurements than before.
Thereafter, I investigated new materials which are expected to manifest novel properties originated from degrees of freedom on multipoles in strongly correlated 4f-electron systems. Particularly, cubic compounds which include Pr, Nd, and Sm elements are highly suitable to this study. I succeeded to synthesize many polycrystalline and single-crystalline samples like new compounds NdNb2Al20 and SmNb2Al20 in my special method. A lot of samples over a hundred were synthesized finally, and their intriguing properties at LT have been found in the research.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，0.1 Kに至る極低温での熱・熱電物性量を測定するにより，4f電子系化合物の新奇な熱電現象を複数見出すことができた。極低温での測定は，熱揺らぎに遮られる磁気モーメントや電子分布などの量子的自由度の異常な揺らぎを観測したいがためであり，100種類を超える化合物を作製し，量子揺らぎに起因すると思われる異常現象を複数とらえた。熱電能は温度差で起電力が生じるという基礎的物理量であるが，現在0.1Kの極低温までの測定を行える研究者は少数であり，独特な情報を得ることができた点学術的意義は大きい。また，将来を見据え，極寒の宇宙空間では，大きな熱電能を示す物質＝熱電素子としての有用性は大きい。
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