| Project/Area Number |
15340116
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NAKAZAWA Yasuhiro Tokyo Institute of Technology, Graduate School of Science and Enginerring, Associate Professor, 大学院・理工学研究科, 助教授 (60222163)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,900,000 (Direct Cost: ¥14,900,000)
Fiscal Year 2004: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2003: ¥12,200,000 (Direct Cost: ¥12,200,000)
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| Keywords | heat capacity / superconductivity / electronic heat capacity coefficient / incommensurate / インコメンシュレート / マイクロチップカロリーメーター / ホールドープ / 電子状態 |
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| Research Abstract |
In this project, we aim at designing calorimeter for measuring heat capacities of small single crystals of organic superconductors. In the former half of the research period, we constructed calorimeter available under magnetic fields up to 15T, and then we measured the samples of organic salts of which donor and anion ratio is non-stoichiometric.
At first, we studied (MDT-TSF)(AuI_2)_<0.436> (T_c=4.3K) and observed a broad maximum at about 3.8K. Although the peak itself is broadened, the magnetic field dependence was observed up to 6T which is consistent with the magnetic and transport behaviors. Since the incommensurate relation between donor layers and anion layers, the electrons in the donor layers feels a kind of random potential and intrinsic peak-broadening effect seems to be occurring in this salt. The heat capacity of κ-(BEDT-TTF)_4Hg_<2.89>Br_8 is also studied. In addition to the incommensurate effect appears as a peak-broadening of the superconductive transitions, we have observed that the electronic heat capacity coefficient is enhanced up to the 50 mJK^<-2>mol^<-1>. The drastic cooling rate dependence of heat capacity anomalies around the superconductive transition temperature is also observed.
The technique developed through this project is available to the other molecular materials which usually yielded as a small pieces of crystals.
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