| Project/Area Number |
17310068
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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 |
Nanomaterials/Nanobioscience
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| Research Institution | Yokohama National University |
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Principal Investigator |
TAKEDA Jun Yokohama National University, Graduate School of Engineering, Professor (60202165)
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| Co-Investigator(Kenkyū-buntansha) |
OHNO Kaoru National University Corporation Yokohama, Graduate School of Engineering, Professor (40185343)
MARUO Shoji National University Corporation Yokohama, Graduate School of Engineering, Associated Professor (00314047)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,370,000 (Direct Cost: ¥14,800,000、Indirect Cost: ¥570,000)
Fiscal Year 2007: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2006: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2005: ¥10,000,000 (Direct Cost: ¥10,000,000)
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| Keywords | Organic Radical / TTTA / Two-Photon Absorption / Photoinduced Phase Transition / Optical Nonlinearity / Magnetic Control / Micro-Machine |
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| Research Abstract |
Since a large first order magnetic phase transition with a wide thermal hysteresis loop over wide temperature range was found in 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) crystal, an organic radical crystal is expected to be a new type of strong correlated electronic systems showing photoinduced phase transition (PIPT) phenomena. In this research, we explore how to control the magnetic properties of TTTA in nano- and micro-regions with large optical nonlinearity, and demonstrate a new approach for the development of functional nano and micromachines by utilizing the PIPT phenomena.
Photoluminescence as well as photoinduced diamagnetic to paramagnetic phase transition in TTTA crystal has been studied in detail under two-photon absorption with different photon densities and wavelengths. Below the threshold photon density to drive the PIPT, the diamagnetic phase shows a broad luminescence band with a large Stokes shift, whose intensity obeys almost second power law of the excitation photon density. Above the threshold photon density, on the other hand, the diamagnetic to paramagnetic phase transition effectively takes place with a large conversion yield and a steep response instead of an occurrence of the photoluminescence, indicating that the phase transition is optically induced by two-photon absorption with large optical nonlinearity. Using the PIPT behavior with the large nonlinearity, the magnetic properties of TTTA can be controlled at room temperature.
In order to develop the functional nano and micromachines, TTTA is distributed into UV curable resins, which are suitable for the production of 3D micromachines by using two-photon microstereolithography. We found that TTTA can be successfully distributed into the resins with keeping the PIPT characteristics by irradiation of intense laser pulses from a femtosecond regenerative amplifier.
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