| Project/Area Number |
23540413
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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 | Ibaraki University |
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Principal Investigator |
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| Co-Investigator(Renkei-kenkyūsha) |
SHIMIZU Katsuya 大阪大学, 大学院・基礎工学研究科, 教授 (70283736)
KAGAYAMA Tomoko 大阪大学, 大学院・基礎工学研究科, 准教授 (40274675)
MATSUMURA Takeshi 広島大学, 大学院・先端物質科学研究科, 准教授 (00312546)
MICHIMURA Shinji 埼玉大学, 科学分析支援センター, 助教 (40552310)
OHOYAMA Kenji 東北大学, 原子分子材料科学高等研究機構, 准教授 (60241569)
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| Project Period (FY) |
2011 – 2013
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| Project Status |
Completed (Fiscal Year 2013)
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| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2011: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 強相関電子系 / 近藤半導体 / 超伝導 / 高圧力 / 磁性 / 準周期 / ステップ磁化 |
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| Research Abstract |
We have succeeded in exhibition of dramatic semiconductor-to-metal transition at 160 GPa and appearance of superconductivity at 195 GPa in Kondo semiconductor YbB_12 which has a small energy gap (E_g/k_B ~ 200 K). Superconducting transition temperature is of about 0.8 K and its critical field is evaluated to be 800 Oe. This transition under ultra high-pressure environment can be observed by using a specialized diamond anvil cell (DAC) technique. In the magnetization response of YbB_12 up to 120 T, the magnetization steeply jumps up at B = 50 T, and continues to increase linearly. This magnetization dose not seem to saturate around B = 120 T. It would be necessary for magnetic saturation to apply the external field B = 200 - 300 T.
As for TmB_4, although the magnetic quasi-crystal lattice characterized by a Fibonacci sequence was found in the phase VII, it is found out that this magnetic phase becomes more stable up to P = 3 GPa.
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