| Project/Area Number |
17540324
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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 | Osaka University |
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Principal Investigator |
SUGIYAMA Kiyohiro Osaka University, Graduate School of Science, Associate Professor, 理学研究科, 助教授 (00187676)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Dai Tohoku University, Institute for Material Research, Assistant Professor, 金属材料研究所, 助手 (30359541)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | High Magnetic Field / Transuranium compounds / Neptunium / Measurements of Magnetization / Strongly Correlated Electron Systems / Metamagnetism / Magnetic Anisotropy / Quatrupolar Interaction |
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| Research Abstract |
We measured high-field magnetization in NpRhGa_5 and NpO_2 and related compound, UO_2. The New transient memory equipment 'Sigma90' was introduced, which was too expensive to buy with this foundation, and developed the related measurement systems by this foundation. Then high-quality magnetization data can be obtained with this new measurement system. The magnetic phase diagram of NpRhGa_5 is obtained by the measurement of the temperature dependence of the high-field magnetization. According to this results, the large magnetic moment of about 1 μ_B/Np with magnetic anisotropy of [110] changes to the small magnetic moment of about 0.5 μ_B/Np with no magnetic anisotropy at the metamagnetic first order transition. The ground state of low temperature state is represented by the theory of Kiss and Kuramoto with the quadrupolar interaction. This means that the system can be explained by the local moment 5f-electron model. On the other hand, the de Haas-van Alphen oscillations are measured and this results shows the 5f-electron is itinerant. These results shows that the magnetism of this compound cannot be explained by the simple localized or itinerant f-electron model. The magnetization of NpO_2 shows always linear below T_N.. This result shows the antiferromagnetic interaction between 5f-electrons is very strong. These results are represented in the international conferences, SCES05 (Vienna ), Handai forum (Hanoi), ICM2006 (Kyoto) and RHMF2006 (Sendai). These results also be represented in the JPS meetings.
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