| Project/Area Number |
10640358
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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 | RIKEN (The Institute of Physical and Chemical Research) |
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Principal Investigator |
HAGIWARA Masayuki RIKEN (The Institute of Physical and Chemical Research) Magnetic Materials Laboratory Senior Scientist, 磁性研究室, 副主任研究員 (10221491)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1998: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Bond alternating chain / Magnetization plateau / Affleck-Haldane conjecture / Spin alternating chain / Quantum ferrimagnet / Spin ladder / Tomonaga-Luttinger liquid / Zigzag ladder / 不純物置換 / 基底状態 / シングレットダイマー相 / 磁場中比熱 / 反強磁性ボンド交替鎖 / 量子フェリ磁性鎖 / 梯子鎖 / 量子磁性体 / NMR / シングレット基底状態 |
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| Research Abstract |
We investigated some nickel and copper complexes which are regarded as the S=1 antiferromagnetic bond alternating chains, the S-1/2 and 1 spin alternating chain, the S=1/2 ferromagnetic-ferromagnetic-antiferromagnetic-antiferromagnetic (F-F-AF-AF) chain, the S=1/2 two-leg spin ladder and the S=1/2 zigzag chain.
We performed susceptibility and magnetization measurements on the S=1 bond alternating chains and compared the experimental results with the calculated ones. Then, the bond alternating ratios and the exchange constants are evaluated. Some of the remarkable findings in this study are the observation of the 1/2 magnetization plateau which corresponds to the quantization of magnetization and the experimental verification of the Affleck-Haldane conjecture by the observation of the gapless behavior in a certain nickel bond alternating chain compound. Moreover, we got evidence for the singlet-dimer ground state in an S=1 bond alternating chain.
The second and the third compounds are related to the studies on quantum ferrimagnets. The temperature dependence of magnetic susceptibility times temperature in each compound is typical of the ferrimagnetic chain. In the S=1/2 F-F-AF-AF chain compound, we observed a steep increase of magnetization around the saturation field and discussed it in terms of the extremely short correlation length.
For the S=1/2 two-leg ladder compound, we performed susceptibility and specific heat measurements and compared the results with the calculated ones. In the gapped phase, the agreement between the experiment and the calculation is excellent, while the agreement becomes poor in the gapless phase that is probably described by the Tomonaga-Luttinger liquid. We discussed this deviation in terms of a recent theory and a NMR experiment.
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