2004 Fiscal Year Final Research Report Summary
Dynamics of electrical conductions for the materials confined in continuous nano-space
| Project/Area Number |
15201019
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nanostructural science
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| Research Institution | Tohoku University |
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Principal Investigator |
TOYOTA Naoki Tohoku University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (50124607)
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| Co-Investigator(Kenkyū-buntansha) |
KURODA Noritaka Kumamoto University, Department of Mechanical Engineering and Materials Science, Professor, 工学部, 教授 (40005963)
MATSUI Hiroshi Tohoku University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (30275292)
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| Project Period (FY) |
2003 – 2004
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| Keywords | mesoporous / zeolite / nanowire / terahertz / complex conductivity / dynamics / low-dimensional |
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| Research Abstract |
In the mesoporous carbon CMK systems, there exist a wide variety of structures. We have carried out the measurements on the electrical conductivities and magnetic susceptibilities in these CMK systems. As a result, we have clarified that low-temperature conducting properties are caused by a two-dimensional variable range hopping mechanism. Under zero-field cooling, the magnetic susceptibility takes a maximum in the vicinity of 60K though, under field cooling, the susceptibilities only exhibit an increase. These facts indicate a formation of spin-glass states in these mesoporous carbon systems. We expect that the spin originates from non-bonding π-electrons in graphen sheets composing the mesoporous structure.
In order to detect dynamical properties of low-dimensional electronic systems, we have realized spectroscopic measurement in the range of terahertz frequency. We employ the transmission measurement based on time-domain spectroscopy. The frequency dependence of complex conductivity and complex dielectric constant are determined from 0.1 to 2 THz. Since we have much interests in the low temperature dynamics, the optical cryostat has been installed in the terahertz unit. Now the minimum measuring temperature is achieved to be 2 K. With use of the terahertz spectrometer, we have measured niobium films, self-organizing DNA films and various mesoporous systems to obtain high-frequency dynamics.
In addition, the microwave conductivity and infrared spectra were measured for artificially synthesized dry DNA crystals. We have found the importance of the role of primary hydration even in the dry DNA systems.
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