SUPER-MICRO POINT-CONTACT-SPECTROSCOPY
| Project/Area Number |
62540247
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
YONEMITSU K. Professor, 理学部, 教授 (10087033)
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| Co-Investigator(Kenkyū-buntansha) |
SHIOZAKI I. Research Associate, 理学部, 助手 (10087166)
SAKAMOTO I. Research Associate, 理学部, 助手 (80094267)
佐藤 英行 東京都立大学, 理学部, 助教授 (80106608)
SATO H. Associated professor
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1988: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Point-Contact-Spectroscopy / NdCu_6 / Non-linear resistance / 点接触スペクトロスコピー / エレクトローフォノン相互作用 / エレクトロンーフォノン相互作用 |
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| Research Abstract |
A Point-Contact-Spectrometer was developed. The needle and anvil are computer controlled to vertical and horizontal directions. A rough vertical control upto 1mum is made by a pulse-mortor and screw system. Finer control is made by two piezo-actuators, one for vertical motion and another for horizontal notion. The control precision of these actuators are 0.1 nm. The maximum span of the vertical actuator is <plus-minus>1.5 mum and that of the horizontal actuator is <plus-minus>3
Using the spectrometer, we measured the PCS of NdCu_6, between 1.6-10.OK. A nutron diffraction study has revealed that the 4f level in Nd ions splits to several levels in the crystal field. We expected to observe in the PCS spectrum structures which correspond to those levels since the residual resistivity ratios of the samples used were from 40 to 60, and samples were in diffusion regime at the measurement temperature. NdCu_6 makes a magnetic transition at Tc=5.9K, and shows rapid resistivity increase just below
… More
Tc. It was afraid that the effect of the rapid increase would disturb the PCS curve to mask the signals to be studied. We made a computation following the Holm-Verkin's scheme and found that the effect of the magnetic transition would be 1. At fairly low temperature (T<<Tc) and when the residual resistivity pi is very small, a voltage jump in the PCS signal should be observed. 2. At higher temperature and when residual resistivity is larger, a sharp positive peak followed by a sharp negative peak must be observed. 3. At higher temperature (but still T<Tc) and when residual resistivity becomes larger, the negative peak attenuats while the high positive peak is still observable. Above Tc, both peaks disappears. According the criteria, we can discriminate wanted peaks from those due to the magnetic transition. Of 56 runs, we selected 11 runs which of we can convince there are no traces of the magnetic transition. We took an average of them and got two peaks at 2mV and 4mV. The result agrees well with the expectation from the nutron diffraction study. Less
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Report
(3 results)
Research Products
(7 results)
