| Project/Area Number |
04640322
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Institute for Materials Research, Tohoku University |
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Principal Investigator |
TOYOTA Naoki Instirite for Materials Research, Associate Prof., 金属材料研究所, 助教授 (50124607)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yosuke Institute for Materials Research, Assistant, 金属材料研究所, 助手 (00167181)
SASAKI Takahiko Institute for Materials Research, Assistant, 金属材料研究所, 助手 (20241565)
LANG Michael 東北大学, 金属材料研究所, 助手 (60240397)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1993: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Organic conductor / BEDFTTF Salt / (BEOT-TTF)_2KHg(SCN)_4 / anti-ferromagnetic metal, quantum oscillation / 量子振動効果 / スピン密度波 |
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| Research Abstract |
This research aims to study an organic conductor (BEDT-TTF) 2KHg-(SCN)4 which takes a phase transition from paramagnetic normal metal to antiferromagnetic metal at about 10K.This material, a typical quasi-two-dimensional conductor as well as other BEDT-TTF salts, shows quite unique properties such as, anomalous magnetoresistance below the transition point, splitting in the de-Haas quantum oscillations, and the reentrance to the normal metallic state above twenty several Tesla at low temperatures. We have studied these properties from the viewpoint of low-dimensional electronic states where closed 2D and open 1D Fermi surfaces coexist. We summarize the results as follows.
1. We have found sharp increase in the Hall coefficient below the transition temperature. This suggests that the significant amount of carriers disappears, being not inconsistent with the appearance of spin- or charge-density-wave.
2. We have systematically explained the origin of the splitting of de-Haas oscillations in terms of the positive (ferromagnetic) exchange interaction acting between the lower and upper Zeeman levels.
3. Detailed studies for the in-plane current-direction dependence and the angular dependent oscillations of the magnetoresistance suggests that a new open orbit appears in the low temperature phase, pointing to the possible lattice displacement accompanied with the transition. We have pointed out the model on a basis of the coexistent SDW and CDW.
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