Scaling Law on the temperature and magnetic field dependence of critical current density in the mixed state of superconductors
| Project/Area Number |
15560279
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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 | Kumamoto University |
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Principal Investigator |
FUJIYOSI Takanori Kumamoto University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (80212190)
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| Co-Investigator(Kenkyū-buntansha) |
SUEYOSHI Tetsuro Kumamoto University, Graduate School of Science and Technology, Assistant Professor, 大学院・自然科学研究科, 助手 (20315287)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Superconductor / Critical current density / Scaling law / Electric transport property / nano-structure artificial pinning / columnar defect / 電圧-電流特性 / 高温超伝導体 |
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| Research Abstract |
1. A theoretical expression for the dependences on the temperature, T, and the flux density, B, of the critical current density, J_c, observed at the value of the electric field E=E_c in the high temperature cuprate superconductors was derived by using a generalized theory of the Glass-Liquid Transition proposed by us, under the assumption that the scaling law of E against J near the G-L Transition can be approximately applied down to fairly low temperatures. It is shown that the derived expression for the scaling law for the T and B dependences of J_c in the high temperature cuprate superconductors is noticeably different from that for the metallic superconductors.
2. We have studied the effect of the densities of columnar defects on pinning parameters in YBa_2Cu_3O_7 thin films prepared by the PLD method with the transport measurements. In order to produce the defects artificially in a controlled manner, the heavy-ions were irradiated onto the films. The critical current density J_c i
… More
ncreases with the doses of the irradiation due to the introduction of the strong pinning sites into samples. These results could be described by the percolation model as a variation of pinning strength distribution affected from the induced defects.
3. ErBa_2Cu_3O_y (ErBCO) thin films with BaZrO_3(BZO) nano-rods were prepared by a PLD method for an enhancement of critical current density J_c. The values of J_c for the ErBCO thin film containing 1.5wt% BZO (Er15) in magnetic fields are higher than those for the ErBCO thin film containing 0.5wt% BZO (Er05). The peaks of J_c have been observed in the angular dependence of J_c in both the films when the magnetic field is applied parallel to the c-axis. It has been found that the peak is attributed to the flux pinning by BZO nano-rods oriented parallel to the c-axis. The peak of the pinning parameter has been observed in the magnetic field dependence. This fact is probably due to the matching the density of BZO nano-rods with that of fluxoids, which was confirmed by TEM observations. Less
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Report
(4 results)
Research Products
(37 results)
