| Project/Area Number |
15540341
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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 |
Condensed matter physics II
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| Research Institution | Osaka University |
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Principal Investigator |
ISHIZUKA Mamoru Osaka University, Graduate School of Engineering Science, Associate Professor, 大学院・基礎工学研究科, 助教授 (30184542)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2004: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | high pressure / diamond-anvil cell / magnetic measurement / SQUID / vibrating coil magnetometer / composite gasket / NiCrAl / 高圧 / 磁化測定 / 反強磁性体 |
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| Research Abstract |
The goal of the project is to improve the sensitivity and the accuracy of high-pressure magnetic measurements in a diamond anvil cell, based on the technology of the SQUID vibrating coil magnetometer.
1. One part of the lead wire of the detection coil is set to move freely for vibration of the detection coil. Newly designed hardware for clamping the end of the moving part is succeeded to suppress an irregular swing of the lead wire, so that the signal-to-noise ratio of the magnetic measurements increases remarkably.
2. Using a press-fit method, a compact mechanical fixing of the diamond-anvils to the pistons has been achieved to eliminate the magnetic background due to epoxy bonding using Stycast #2850GT. Besides reducing the background signal, the simple structure makes it easy to assemble anvils on the pistons.
3. A composite gasket for precise magnetic measurements at pressures up to around 30 GPa in a diamond-anvil cell has been developed. It was designed so that the load is supported mainly by the inner part made of a NiCrAl alloy, slightly larger than the culets of the anvils, and the CuBe girdle prevents it from fractured. For the gasket thus prepared the magnetic contribution was almost the same as that of a CuBe gasket having the same size, and a thickness of greater than 30 um was assured at 30 GPa.
4. In order to test the performance of the products thus developed we have carried out magnetic susceptibility measurements of Cs_2CuF_4 at various pressures up to 26 GPa and found for the first time a pressure induced magnetic phase transition at around 21 GPa.
We have succeeded to achieve one order improvement of the accuracy of the measurements as well as an increase of the pressure to around 30 GPa for precise magnetic measurements.
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