| Project/Area Number |
14540359
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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 | Kyushu University |
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Principal Investigator |
IDOGAKI Toshihiro Kyushu University, Faculty of Engineering, Prof., 大学院・工学研究院, 教授 (40038013)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Kazuyoshi Kyushu University, Faculty of Engineering, Prof., 大学院・工学研究院, 教授 (10029548)
MURAOKA Yoahinori Ariake National College of Technology, Assoc. Prof., 助教授 (60229953)
TANAKA Akinori Kyushu University, Faculty of Engineering, Research Assoc., 大学院・工学研究院, 助手 (80274512)
KAWAE Ttsuya Kyushu University, Faculty of Engineering, Assoc. Prof., 大学院・工学研究院, 助教授 (30253503)
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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 |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Competing Spin System / Dipole / Quadrupole / Partially Disorered Phase / Staggered Ordering |
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| Research Abstract |
In the present study, we performed through and systematic investigations of the stability and the physical origin of characteristic types of dipole and/or quadrupole orderings in the systems with frustration inducing bilinear and/or biquadratic exchange interactions.
Main results are as follows ;
1)For bilinear-biquadratic exchange ± J Ising model, we performed the non-equilibrium relaxation MC calculation and clarified that randomness weakens the re-enntrant phenomena of ferromagnetic dipole ordering but not affects on the ataggered quadrupole ordering. The critical exponents depend (not depend) on the randomeness for the dipole (quadrupole) ordering.
2)In order to discuss the partially disordered states in the axial next nearest neighbor Ising (ANNNI) model, we proposed two extended models, i.e. (i) intralayer exchang alternating model and (ii) mixed spin model. By using standard MC and site dependent molecular field calculation, for both models we confirmed the stability of partially disordered states and the importance of entropy contribution for occurence of the partially disordered states.
3)We have investigated the effects of the biquadratic interactions on 3D classical plane rotator model with stacked triangular lattice geometry by use of histogram MC simulation methods. We obtained complete magnetic phase diagrams for the system, and clarified the nature of appearing various pahases including incommensurate-or chiral dipole (quadrupole) ordering, etc.
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