| Project/Area Number |
12640341
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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 | Tokyo University of Science |
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Principal Investigator |
SAKATA Hideaki Tokyo University of Science,Physics,Assosiat,Professor, 理学部, 助教授 (30215636)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Super conductivity / Vortex Latlice / Scanning Tunneling Microscopy / Scanning Tunneling Spectoscopy / boro carbide / YN,B,C / hoauy fermion / CeRu2 / 重い電子系 |
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| Research Abstract |
In this research project, we aimed at observing the dynamical process of the vortex lattice in real space by scanning tunneling spectroscopy (STS). STS measurements were performed on the cut or cracked surface ofYNi_2B_2C and CeRu_2.In the case of YNi_2B_2C, three distinct regions which are superconducting, metallic and semiconducting were observed. The metallic and semiconducting regions are precipitates which have slightly different compositions from YNi_2B_2C. Under the magnetic field applied above T_c, the vortices were imaged in the superconducting regions as the increase in the local density of states (LDOS) at Fermi energy. We have observed the phase transition from triangular to square vortex lattice induced by the external magnetic fields in real space. Furthermore, when the applied magnetic field is increased at 4.2K, the LDOS was enhanced along the boundary of the semiconducting precipitates. This enhancement of the LDOS is attributed to a number of pinned vortices at the boundary.
We have also succeeded in observing the vortex lattice in CeRu_2 by STS for the first time. The metallic precipitates are observed on the surface. We claimed that such structures affect the anomalous vortex pinning in this material.
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