| Project/Area Number |
20740192
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Condensed matter physics II
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| Research Institution | Hokkaido University |
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Principal Investigator |
YANAGISAWA Tatsuya Hokkaido University, 創成研究機構, 特任助教 (10456353)
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| Co-Investigator(Renkei-kenkyūsha) |
GOTO Terutaka 新潟大学, 大学院・自然科学研究科, 教授 (60134053)
TAKEDA Naoya 新潟大学, 工学部, 教授 (80242171)
NEMOTO Yuichi 新潟大学, 大学院・自然科学研究科, 准教授 (10303174)
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| Research Collaborator |
MAPLE M. Brian カリフォルニア大学サンディエゴ校, 物理学科, 教授
E. BAUMBACH Ryan カリフォルニア大学サンディエゴ校, 物理学科, 博士研究員
HO Pei-Chun カリフォルニア州立大学フレズノ校, 物理学科, 准教授
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| Project Period (FY) |
2008 – 2009
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| Project Status |
Completed (Fiscal Year 2009)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2009: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2008: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 強相関系 / ラットリング / 超音波 / 充填スクッテルダイト / カゴ状化合物 / 電子-格子相互作用 / アメリカ:ポーランド / 超伝導 / 国際情報交換 / アメリカ : ポーランド |
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| Research Abstract |
Ultrasonic measurements on the Filled-Skutterudite compounds Pr_<1-x>NdxOs_4Sb_<12>(x=0.45, 0.25, 1.0)have been performed. Frequency dependences of elastic constant C11 were investigated with longitudinal ultrasonic frequencies varying between 34 to 245 MHz on these samples. A characteristic ultrasonic dispersion, which had also been observed in PrOs_4Sb_<12> (x=0) at around 30K, is also observed in the dilute systems and shifts gradually to higher temperature with increasing the Nd concentration x. On the other hand, the C11 of x=0.45 sample shows softening and levels off feature at T=0.25K. This result implies that the Nd3+ ion's degenerate CEF ground state is split due to some order even in the Pr^<3+> ion's contribution to SC. In addition, a magnetically robust elastic softening of C11 was found in the end material NdOs_4Sb_<12> (x=1.0) under magnetic field 2 T<H<10T at low temperature T<1K, which suggest a presence of the off-center tunneling as same as LaOs_4Sb_<12> and PrOs_4Sb_<12>. Above results imply that an origin of the heavy-fermion state of NdOs_4Sb_<12> could possibly be related to a degenerate quantum ground state due to the off-center degrees of freedom.
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