| Project/Area Number |
13554012
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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 | 展開研究 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | High Energy Accelerator Research Organization (2003)
The University of Tokyo (2001-2002) |
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Principal Investigator |
ONO Kanta High Energy Accelerator Research Organization, Institute of Materials Structure Science, Associate Professor (70282572)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥12,700,000 (Direct Cost: ¥12,700,000)
Fiscal Year 2003: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2002: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2001: ¥7,300,000 (Direct Cost: ¥7,300,000)
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| Keywords | nanomaterials / halfmetal / spinelectronics / MnAs / 金属ドット / ナノスケール / 閃亜鉛鉱型 / 有機金属化学 / 閃亜鉛鉱型MnAsドット / 放射光光電子分光 / SmCo磁性微粒子 / MnPt磁性微粒子 / 放射光光電子顕微鏡 / ナノスケール磁性ドット / スピントロニクス材料 / 放射光解析 |
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| Research Abstract |
NiAs-type Mn pnictide fibres grown on GaAs substrates by molecular-beam epitaxy (MBE) have been extensively studied because of their potential as spintronic device applications utilizing ferromagnetic metal-semiconductor hybrid structures. Among them MnAs and MnSb have a higher potential for spintronic devices due to their high Curie temperatures Tc (MnAs: Tc~320K, MnSb: Tc~600 K). Basic physical properties of MnAs films including the consecutive phase transitions between the NiAs-MnP-liAs type crystalline structures in the bulk have been investigated. The electronic structure of MBE-grown Mn pnictides films has also been investigated by photoemission spectroscopy including spin-resolved measurements.
At first, ferromagnetic nanoscale zinc-blende MnAs dots were successfully fabricated on a sulfur-passivated GaAs (001) surface by molecular-beam epitaxy. Transmission electron microscopy and selected area electron diffraction showed that the crystalline structure was not the same as that of bulk MnAs with NiAs-type hexagonal crystalline structure, but of zinc-blende type. In in situ photoemission spectroscopy of the zinc-blende MnAs dots, the Fermi edge was not clearly observed and the Mn 3d partial density of states was similar to that of the diluted ferromagnetic semiconductor Gal-xMnxAs, which also supports the fabrication of zinc-Hende MnAs in the nanoscale.
In the second step, we have synthesized Mn-Pt nanoparticles using a chemical preparation based on a liquid-phase reaction caused by decomposition of organometallic precursors. The synthesized monodisperse Mn52.5Pt47.5 nanoparticles show an fcc crystalline structure and ferromagnetic properties even at the room temperature. Mn52.5Pt47.5, which is not ferromagnetic in a bulk form, shows a completely different physical property in nanparticles.
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