| Project/Area Number |
13650026
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
表面界面物性
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| Research Institution | Osaka University |
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Principal Investigator |
NAKANISHI Hiroshi OSAKA UNIVERSITY, GRADUATE SCHOOL OF ENGINEERING, INSTRUCTOR (ASSISTANT PROFESSOR), 大学院・工学研究科, 助手 (40237326)
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| Co-Investigator(Kenkyū-buntansha) |
KASAI Hideaki OSAKA UNIVERSITY, GRADUATE SCHOOL OF ENGIINEERING, PROFESSOR, 大学院・工学研究科, 教授 (00177354)
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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 |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | ATOM BRIDGE / NANO WIRE / MAGNETISM / STM / FIRST PRINCIPLES CALCULATION / SPINTRONICS / ALLOY / SPIN DEPENDENT QUANTUM CONDUCTANCE / 鉄 / ニッケル / 量子化電気伝導 / 構造安定性 |
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| Research Abstract |
We investigated the nano-physics : nano-lattice-structure, nano-magnetism, and quantum transport, of the magnetic atom bridges constructed between a tip of a scanning tunneling microscope (STM) and a solid surface with the aid of first-principles calculation based on the density functional theory.
We show the origin of a change in the magnetic state induced by the STM-tip manipulation and how the change in the magnetic state affects the electron transport phenomena by use of the Fe atom bridge of the simple structure, the linear chain structure. As a result of total energy calculation, the Fe atom bridge of the linear chain structure is unstable and its lattice is too weak to show the change in the magnetic state. The stable atom bridge is of the zigzag chain structure, whose magnetic state is always high-spin ferromagnetic state
We searched the stable structure of the atom bridge whose lattice structure is enough strong to show a change in the magnetic state. We have found such a stable
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structure. That is the twisted ladder structure. The Fe atom bridge with a twisted ladder structure is stable enough to undergo changes in its magnetic state via compression in length. We showed that it is possible to control the magnetic state by the STM-tip manipulations.
We have also investigated the magnetic properties of magnetic alloy atom bridges. In the case of an Fe_<1-x>Ni_x alloy atom bridge, we have found that the atoms maintain a considerably large magnetic moment (about 3μB for an Fe atom and about 0.9μB for a Ni atom), and that the mean magnetic moment per atom in the atom bridge decreases linearly as x increases. In the case of an Fe_xV_<1-x> alloy atom bridges shows a strong contrast with that of the Fe_<1-x>Ni_x alloy atom bridges, and similarities with the bulk of the corresponding alloy, except for the case of x=1.0. In the Fe_<1-x>V_x alloy atom bridge, a V atom has no magnetic moment, and an Fe atom has a smaller magnetic moment than that in the bulk Fe crystal. The magnetic moment of the Fe atom in the Fe-V alloy atom bridge is strongly reduced by the Fe-V atom mixing. These results give us the atom bridge version of the Pauling-Slater curve.
Furthermore, we have determined the spin transport phenomena trough these atom bridges. We think that such a systematic investigation gives us the important and useful information in order to establish a basis for the design and fabrication of the atom bridge related nano-spin-electronics devices. Less
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