| Project/Area Number |
08640445
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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 | University of Tokyo |
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Principal Investigator |
TAKAHASHI Minoru The Univ.of Tokyo, Inst.for Solid State Physics, Professor, 物性研究所, 教授 (40029731)
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| Co-Investigator(Kenkyū-buntansha) |
KAWARABAYASHI Tohru The Univ.of Tokyo, Inst.for Solid State Physics, Research Associate, Assistant P, 物性研究所, 助手 (90251488)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
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| Keywords | Spin chain / Heisenberg model / Scaling / Magnetization curve / Ladder model / Dimer state / ダイヤー状態 / 熱力学ベ-テ仮説方程式 / スケーリング関数 / 強磁性ハイゼンベルグ鎖 / 反強磁性ハイゼンベルグ鎖 / ボナ-フィッシャー曲線 / 長距離相互作用 |
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| Research Abstract |
1. Critical phenomena of S=1 bond-altenating chain and analysis of experimental results
S=1 antiferromagnetic chain has the energy gap. But it was expected that the alternating bond chain may become gapless at some strength of the alternation. We find that Ni(333-tet)(mu-N_3)(ClO_4)is such a chain with bond alternation. We did the Monte Carlo calculation and the exact diagonalization calculation and compared with experimental results by Hagiwara's group. The coincidence is very good.
2. Study of spin systems with long range interaction
Properties of the system with long-range interaction are quite different from those of systems with short-range interaction. Generally the short-range interacting spin systems have not phase transition in one and two dimensions. We investigated the low-temperature behavior of correlation length and phase transition of the system with long-range interaction using several approximations.
3. Universal magnetic scaling function of ferromagnetic Heisenberg chain
M
… More
agnetization curve of ferromagnetic Heisenberg model at low temperature approaches to some universal scaling function regardless to the fact that the system is classical or quantum. M=M<@D20phiM@>D2(<@D7P<@D2z@>D2H(/)T<@D12@>D1@>D7, <@D7P<@D2z@>D2(/)LT@>D7). Here rho<@D2s@>D2 is the stiffness constant, H is magnetic field, T is the temperature, L is the length of the system, M<@D20@>D2 is the saturation magnetization. We got phi<@D2M@>D2 (g, 0) = <@D72(/)3@>D7g - <@D744(/)135@>D7g<@D13@>D1 + <@D7752(/)2835@>D7g<@D15@>D1 - <@D7465704(/)1913625@>D7g<@D17@>D1 + <@D7356656(/)1515591@>D7g<@D19@>D1 - <@D7707126486624(/)3016973334375@>D7g<@D111@>D1 + <@D71126858624(/)4736221875@>D7g<@D113@>D1 - <@D75083735857217648(/)20771861407171875@>D7g<@D115@>D1 + ・・
4. Numerical analysis of Anderson transiton in random magnetic field
We analyzed the critical exponents of Anderson transition in random magnetic field using the transfer matrix method. We certified the universality of the Anderson transition in the unitary class. Less
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