2003 Fiscal Year Final Research Report Summary
ELECTRON CORRELATION AND DESIGH OF CLUSTERES STABILIZED IN PERIODIC NANOSPACE OF ZEOLITE CRYSTALS
| Project/Area Number |
13304027
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
NOZUE Yasuo OSAKA UNIVERSITY, GRADUATE SCHOOL OF SCIENCE, PROFESSOR, 大学院・理学研究科, 教授 (60125630)
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| Co-Investigator(Kenkyū-buntansha) |
ARITA Ryotaro UNUVERSITY OF TOKYO, GRADUATE SCHOOL OF SCIENCE, ASSISTANT PROFESSOR, 大学院・理学系研究科, 助手 (80332592)
OTO Kenichi OSAKA UNIVERSITY, FACULTY OF SCIRENCE, ASSOCIATE PROFESSOR, 理学部, 助教授 (30263198)
AOKI Hideo OSAKA UNIVERSITY, GRADUATE SCHOOL OF SCIENCE, PROFESSOR, 大学院・理学系研究科, 教授 (50114351)
ARAKI Shingo OSAKA UNIVERSITY, GRADUATE SCHOOL OF SCIENCE, ASSISTANT PROFESSOR, 大学院・理学研究科, 助手 (90362615)
NAKANO Takehito OSAKA UNIVERSITY, GRADUATE SCHOOL OF SCIENCE, ASSISTANT PROFESSOR, 大学院・理学研究科, 助手 (50362611)
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| Project Period (FY) |
2001 – 2003
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| Keywords | cluster / zeolite / ferromagnetism / μSR / electron spin resonance / orbital degeneracy / spin-orbit interaction / electron correlation |
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| Research Abstract |
A ferromagnetism has been observed potassium nanoclusters stabilized in cages of aluminosilicate zeolite LTA, when the average s-electron number of clusters exceeds 2. In the present research, the g-value of electron spin resonance was found to decrease when the average s-electron number exceeds 2. The s-electrons more than 2 per cluster occupy 1p-like orbital of cluster. The origin of ferromagnetism is assigned to the canting of antiferromagnetically ordered spins, because the antisymmetric exchange interaction can be enhanced strongly by the degeneracy of 1p-like orbital. The canting model is supported by the magnetization process at high magnetic fields. The μSR study of potassium clusters was performed, and the local magnetic field and its dynamics were analyzed. The results were well consistent with above magnetic model. At the same time, the increase in the asymmetry of μSR signal was observed when a very weak longitudinal magnetic field was applied. This behavior was assigned to the orientation of spontaneous magnetization generated by the spin-canting. The first-principles band calculations were performed for the potassium clusters stabilized in the zeolite LTA. A very simple band structure was obtained indicating that the model of superatom crystal was found to be applicable to this system. The energy band width was much narrower than the electron repulsion energy of electrons confined in the same cluster. The spatial distribution of the edge state in the quantum Hall regime was studied by the magnetocapacitance technique by the use of the thin-wire multigate along the sample boundary. The breakdown of the quantum Hall effect was studied in terms of the sample width dependence. The origin of sub-linear dependence on the sample width was assigned to the bulk nature of the two-dimensional electron system.
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