| Project/Area Number |
02650519
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
金属材料(含表面処理・腐食防食)
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
YOSHIDA Katsukuni Kyoto University, Institute of Atomic Energy, Associate Professor, 原子エネルギー研究所, 助教授 (70027142)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
UEDA Sizumasa Kyoto University, Institute of Atomic Energy, Technician, 原子エネルギー研究所, 教務職員 (00093196)
TOMII Yoichi Kyoto University, Faculty of Engineering, Lecturer, 工学部, 講師 (90026245)
|
|---|
| Project Period (FY) |
1990 – 1991
|
| Project Status |
Completed (Fiscal Year 1991)
|
| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
|
|---|
| Keywords | Percolation / Multiphase Materials / High T_c Superconductor / Clusters / Critical Current / Bi-Pb-Sr-Ca-Cu-O oxide / Ag Doping / Crystalline Junction / Bi系超伝導酸化物 / 臨界電流の温度依存性 / 転移温度の電流依存性 |
|---|
| Research Abstract |
In order to reveal the problem of how the behavior of constituent phases in multiphase superconductors characterizes the superconducting properties, an experimental study was made of the network structure of the crystalline clusters of the high T_2 oxide of Bi-(Pb)-Sr-Ca-Cu-0 systems(By systems), to which oxide Ag_2O was doped. We investigated this problem in particular reference to the percolation process of the clusters, where the superconducting junction between adjacent crystallines plays an important role. Main results are sunynarized as follows. 1. A small amount of doped Ag, which was produced by dissolving Ag_2O during the sintering the above Bi compound, exerts a considerable deteriorating effect on the superconducting properties. This effect implies that the superconducting junction between crystallines is largely affected by the presence of nonsuperconducting compound like Ca_2PO_4, formation of which is easily controlled by such doping. 2. The X rgy diffraction does not show any change in the structure of the superconducting crystalline itself, and only demonstrates that the most amount of the doped Ag precipitates as a pure metallic phase. 3. The superconducting properties are remarkably affected also by the process of heat treatment(furnace cooled, air cooled or quenched to liquid nitrogen)after the sintering fabrication of the samples. The faster cooling makes the superconducting properties worse. The heat treatment also strongly controls the crystalline interface. 4. The magneto resistance appearing below the transition temperature T@CCc@DD shows a large hysteresis for the samples with inferior superconducting properties. 5. The samples with good qualities exhibit a large diamagnetic susceptibility characteristic of the intergrain superconducting. 6. The above properties was discussed in terms of the percolation process by modeling a Josephson network.
|
