2002 Fiscal Year Final Research Report Summary
Design and relavization of photo-induced magnetic pole inverison
| Project/Area Number |
12440096
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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 |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HASHIMOTO Kazuhiro Research Center for Advanced Science and Technology, Professor, 先端科学技術研究センター, 教授 (00172859)
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| Co-Investigator(Kenkyū-buntansha) |
OHKOSHI Shin-ichi Research Center for Advanced Science and Technology, Associate Professor, 先端科学技術研究センター, 助教授 (10280801)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Photo magnetism / photo-induced magnetic pole inversion / Ferromagnetism / molecule-based magnet / Cyaro-bridged metal complex |
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| Research Abstract |
To prepare a new magnetic material showing photo-induced magnetic pole inversion, we have studied opto-functionalities of several metal complexes. The photomagnetic effect of the mixed-valence compound Cu^<II>_2 [Mo^<IV>(CN)_8]_8H_2O was observed. The UV-VIS spectra showed the intervalence transfer (IT) band between Mo^<IV>-CN-Cu^<II> and Mo^V-CN-Cu^I around 500 nm. When the paramagnetic compound was irradiated by a filtered blue light of a Xe lamp at 5 K, the irradiated sample exhibited a spontaneous magnetization with a Curie temperature of 17 K. By annealing the irradiated sample above 200 K, the magnetic property of this sample returned to the initial state. Moreover, a new type of cyano-bridged Co-W bimetallic assembly, Cs^I[{Co^<II>(3-cyanopyridine)_2}{W^V(CN)_8}]H_2O was synthesized. This compound exhibited a temperature-induced phase transition and a photo-induced magnetization. Irradiating with light induced a spontaneous magnetization with a magnetic phase transition temperature at 30 K. This photo-induced magnetization is due to the phase transition from Co^<III>(LS ; S = 0)-W^<IV>(S = 0) to Co^<II>(HS ; S = 3/2)-W^V(S = 1/2) phases by the irradiation. Furthermore, we observed the photomagnetic effect in Rb_<0.91>Mn_<1.05>[Fe(CN)_6]・0.6H_2O ferromagnet. Magnetization of this system was reduced by irradiation with only one-shot of laser pulse (532 nm) at 3 K. Infrared spectra before and after the irradiation indicated that this photomagnetic effect was caused by a photo-induced phase transition from the Fe(II)-CN-Mn(III) phase to the Fe(III)-CN-Mn(II) phase.
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