| Project/Area Number |
16560269
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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 |
Electronic materials/Electric materials
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| Research Institution | Yokohama National University |
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Principal Investigator |
TAKEMURA Yasushi Yokohama National University, Graduate School of Engineering, Associate Professor, 大学院・工学研究院, 助教授 (30251763)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | atomic force microscope (AFM) / magnetic tunnel junction / Coulomb blockade / 原子間力顕微鏡(AFM) |
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| Research Abstract |
Well-defined nanostructures of oxide can be fabricated on metal thin films by applying a negative bias on a conductive atomic force microscopy (AFM) cantilever. With using this technique, planar-type magnetic tunnel junctions have been fabricated. The junction area of this structure can be much smaller than that of a conventional multilayer-type junction. This is advantageous for fabrication of single electron devices exhibiting Coulomb blockade. Ni thin film of 8-20 nm were deposited on SiO2/Si substrates by rf magnetron sputtering. The films were patterned to stripe shapes by photolithography and dry etching. Then nanowires of oxide were fabricated by the AFM nano-oxidation technique, and planar-type magnetic tunnel junctions were successfully obtained.
A diode characteristic was observed in current-voltage measurement at the temperature range of 17-300K. It was found that the fabricated nanowires of oxide could be a tunnel barrier. Formally the width of the barrier was thick but the AFM nano-oxidation using tapping mode of the AFM operation realized a thinner width. The barrier height of 1.5 eV and barrier width of 1.7 nm were derived from a calculation using the Simmons formula fitting. There results are promising for ferromagnetic single electron transistors exhibiting Coulomb blockade.
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