| Project/Area Number |
11215202
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (B)
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MINAMI Fujio Department of Physics, Tokyo Institute of Technology, Professor, 大学院・理工学研究科, 教授 (30200083)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKAWA Tadahiko Department of Physics, Tokyo Institute of Technology, Research Associate, 大学院・理工学研究科, 助手 (70313327)
KURODA Takashi Department of Physics, Tokyo Institute of Technology, Research Associate, 大学院・理工学研究科, 助手 (00272659)
KOSHIHARA Shinya Department of Physics, Tokyo Institute of Technology, Research Associate, 大学院・理工学研究科, 教授 (10192056)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥41,200,000 (Direct Cost: ¥41,200,000)
Fiscal Year 2001: ¥20,600,000 (Direct Cost: ¥20,600,000)
Fiscal Year 2000: ¥12,500,000 (Direct Cost: ¥12,500,000)
Fiscal Year 1999: ¥8,100,000 (Direct Cost: ¥8,100,000)
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| Keywords | spin crossover complex / photo-induced phase transition / semimagnetic semiconductor / coherent control / spin dynamics / magnetic polaron / 吸収スペクトル / 励起子 / スピンクロスオーバー物質群 / フェムト秒光パルス / ファラデー回転 / レーザー分光 / 相転移 / 磁性 / 光誘起 |
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| Research Abstract |
Photowithching process between low- and high-spin states in is investigated in spin crossover materials, such as spin crossover complexes and semimagnetic semiconductors. The outline of the achieved results is shown as follows.
(1) Photo-induced magnetic phase transition in spin crossover complexes
Details of the photo-induced magnetic phase transition in Fe^<2+> spin crossover complexes were investigated by measuring absorption spectrum and magnetic susceptibility. In the photoswithing process between low- and high-spin states, nonlinear characteristics such as thresholdlike behavior, incubation period, and phase separation have been observed. These results demonstrate that the cooperative intersystem crossing mediated by spin-lattice interaction plays a key role in driving process of a new class of nonequilibrium phenomena. In addition, it turned out that this photo-induced magnetic phase transition process was greatly influenced by an external magnetic field.
(2) Photo-induced magnetic phase transition in semimagnetic semiconductors
Time-resolved Magneto-photoluminescence experiments were carried out in a semimagnetic semiconductor Cd _<0.9>Mn_<0.1>Te with varing exciton density. A reduction of the Zeeman shift and the binding energy of magnetic polaron is observed. The spectral feature is interpreted by the heating effect of manganese spins. Polarization dependence of the spin heating is observed for the first time, revealing the contribution of spin flip between excitons and magnetic ions to the heating process.
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