| Project/Area Number |
14540341
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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 |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Kyushu Institute Of Technology |
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Principal Investigator |
TAKAGI Seishi Kyushu Institute Of Technology, Faculty of Engineering, Professor, 工学部, 教授 (90112359)
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| Co-Investigator(Kenkyū-buntansha) |
MITO Masaki Kyushu Institute Of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60315108)
DEGUCHI Hiroyuki Kyushu Institute Of Technology, Faculty of Engineering, Professor, 工学部, 教授 (30192206)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | quantum spin system / Haldane materials / quantum ladder materials / spin-Peierls materials / magnetism under pressure / pressure-induced anomalous magnetism / 加圧下単結晶 |
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| Research Abstract |
Spin-gap systems where singlet-ground states are observed because of significant quantum effect have attracted attention in the field of low-dimensional quantum spin materials and organic magnets. We have precisely measured the magnetization and magnetic susceptibility for an organic low-dimensional quantum spin system under pressure and found the anomalous magnetic behavior. The magnetic susceptibility of a typical spin-Peierls substance, MEM-[TCNQ]_2, under pressure increases with decreasing temperature at low temperatures and it is roughly described by Cuire's law.
We have studied to clarify such anomalous magnetic behavior under pressure for two years. Three kinds of spin-gap systems, (1)Haldane substance Ni(C_5H_<14>NQ_2)_2N_3PF_6, (2)quantum ladder substances : Cu_2(C_6H_<12>N_2)_2Cl_4 and related substances, (3)spin-Peierls substances : MEM-[TCNQ]_2 and a related substance, were treated in this study. Good single crystals were made and their magnetic properties were measured precisely as a function of pressure. As a result of the measurement for a single crystal under uniaxial pressure, we found that the magnetic properties of MEM-[TCNQ]_2 show significant anisotropy. In order to clarify the origin of the increase of the magnetic susceptibility under pressure for MEM-[TCNQ]_2, we have measured the electron-spin-resonance (ESR) spectra under uniaxial pressure by using a hand-made pressure cell for a conventional X-band ESR instrument : The temperature dependence of the ESR spectra show that there are two different spins under pressure, which has been supposed by the macroscopic measurement such as the magnetization and magnetic susceptibility.
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