| Project/Area Number |
14540347
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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 |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Asahikawa National College of Technology |
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Principal Investigator |
OKAJIMA Yoshitoshi Asahikawa National College of Technology, Associate Professor, 助教授 (00213934)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | one-dimensional conductor / charge density wave / sliding motion / ring-shaped crystal / Aharonov-Bohm effect / AB effect / アハラノフ・ボーム効果 / 電荷密度数 / リンク状結晶 |
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| Research Abstract |
A tube-shaped single crystal was taken out from a batch of the quasi-one-dimensional conductor NbSe3. The crystal was sliced into several disks by focused ion beam (FIB) milling. Tube-shaped single crystals have a hole along the center axis. The sliced disks also have a hole at the center of them. The part of the disk away from the hole was milled using FIB, and the part near the hole was remained. We have successfully synthesized a ring sample of NbSe3 with a diameter of 〜5μm. The electrical contacts, were taken to the contact pads of the ring sample by evaporating indium. Measurements of resistance were performed by the four-probe method.
Temperature dependence of resistance of the ring sample has been qualitatively the same as that of the whisker-shaped single crystals. Therefore, they are certain that the ring sample is the single crystal of NbSe3, that the charge-density-wave (CDW) transitions take place at the two transition temperatures, and that no damage is induced into the rin
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g sample through the FIB milling. The nonlinear conduction by the CDW sliding has been observed at several temperatures from 41K to 55K in the low-temperature CDW state. The ring sample synthesized in this study is suitable for studying whether the Aharonov-Bohm (AB) effect can be observed in the nonlinear conduction by the CDW sliding.
In the measurements of magnetoresistance, the magnetic field was applied normal to the ring sample and the resistance was measured with changing strength of the magnetic field. The total current through the ring sample was kept constant. The resistance as a function of field strength seemed to show a periodic modulation. However, the modulation with the same amplitude was observed under the constant magnetic fields and constant currents. This fact means that the noise is large compared to the modulation by the magnetic field. Therefore, the periodic modulation of the magnetoresistnce has not been observed.
It is not clarified whether the AB effect can be observed in the nonlinear conduction by the CDW sliding. It is needed that the signal-to-noise ratio is improved. Less
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