2003 Fiscal Year Final Research Report Summary
Study on mechanism and dynamical control of quantum dynamics of magnets
| Project/Area Number |
14540353
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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 |
物性一般(含基礎論)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MIYASHITA Seiji The University of Tokyo, School of Engineering, Professor, 大学院・工学系研究科, 教授 (10143372)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Keiji The University of Tokyo, School of Engineering, Research Associate, 大学院・工学系研究科, 助手 (90312983)
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| Project Period (FY) |
2002 – 2003
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| Keywords | quantum spin systems / Nanoscale molecular magnet / nonadiabatic transition / ESR / quantum dynamics / spin crossover / quantum diffusion / quantum switching |
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| Research Abstract |
We have studied characteristics of quantum magnets. In particular we have studied systems with non-zero magnetization in contrast to the systems consist of the singlet pairs which have been studied widely. We also studied dynamical properties of the systems under time dependent field. As concrete subjects, we studied Spin-Peierls transition in the systems with S=1 or in the quantized phonon systems. We also studied effects of quantum fluctuation in the magnetization process of S=1/2 XY-like Heisenberg antiferromagnetic models where we found various field induced phases. Phase transitions due to the spin-crossover has been studied. We have developed numerical method to study ESR line shape of interaction spin system and studied field-direction dependence of the line shape of an orthogonal-dimer system. We also studied origin of the adiabatic change of magnetization in naoscale magnets and found the Dzyaloshinskii-Moriya interaction plays an important role, but it causes strong field-direction dependence. As a mechanism of field-direction free adiabatic transition we also studied effects of hyperfine interaction. The idea of quantum switching has been proposed. Heat conduction due to spin fluctuation has been also studied.
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