| Project/Area Number |
21540363
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Hiroshima University |
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Principal Investigator |
UMEO Kazunori 広島大学, 自然科学研究支援開発センター, 准教授 (10223596)
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| Co-Investigator(Renkei-kenkyūsha) |
HIROI Zenji 東京大学, 物性研究所, 教授 (30192719)
YAMAURA Jun-ichi 東京大学, 物性研究所, 助教 (80292762)
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| Research Collaborator |
TAKABATAKE Toshiro 広島大学, 大学院・先端物質科学研究科, 教授 (40171540)
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| Project Period (FY) |
2009 – 2011
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| Project Status |
Completed (Fiscal Year 2011)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2011: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2010: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2009: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | 低温物性 / 物性実験 / 超電導材料・素子 / 高圧力物性 / 高圧力 / 比熱 / カゴ状物質 / パイロクロア酸化物 / クラスレート / 超伝導 / ラットリング |
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| Research Abstract |
The caged compound KOs_2O_6 exhibits a superconducting transition at T_c=9.6 K, and a first-order transition at T_p=7.5K, which manifested itself in the sharp peak of the specific heat. In order to examine the relationship between these anomalous properties and low-energy anharmonic vibration of K ions, we measured specific heat under pressure with a high-precision AC calorimeter using a Bridgeman anvil cell. The peak in the specific heat at Tp disappeared at a low pressure of 0.02GPa. Furthermore, Tc increases from 9.65K at P=0 to 9.80K at P=0.02 GPa. This finding suggests that the superconducting state is stabilized by the suppression of the first-order transition at T_p.
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