| Project/Area Number |
09640434
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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 | Osaka University |
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Principal Investigator |
ISHIZUKA Mamoru Osaka Univ., Reseach Center for materials Science at Extreme Condictions, Reserch associate, 極限科学研究センター, 助手 (30184542)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Shoichi Osaka Univ.Research Center for Materials Aciences at Extreme Conditions Professo, 極限科学研究センター, 教授 (10001843)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | high pressure / SQUIDmagnetometer / magnetization measurement / diamond-anvil cell / vanadium / superconducting transition temperature / 磁気測定 |
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| Research Abstract |
We have improved the performance of the high-pressure magnetization measurement system consisting of a diamond-anvil cell (DAC) and a SQUID vibrating coil magnetometer in order to increase the pressure range of a high-pressure research in magnetism and superconductivity to more than 100 GPa. Results are as follows. (1) The sensitivity of the system has been increased by a factor of 10 by compensating the magnetic-field signal which previously prevented us from applying larger magnetic field than 3 Oe. (2) Thermal insulation of the actuators for vibration of the SQUID detection coil from the DAC has been improved, resulting in an increase in the temperature of the measurements by a factor of more than two. (3) Using this system we have investigated a pressure-induced magnetic phase transition in CrTe (T_c=330-350 K) and pressure effect on superconducting transition of vanadium at megabar. A magnetic phase transition in CrTe at around 3.5 GPa was first reported by Grazhdankina et al., but their results are controversial because the sample they used was not single phase and the experimental accuracy seems not to be enough for establishing the magnetic state. We have observed a disappearance of the ferromagnetism of CrTe at 6-7 GPa for samples with good quality. The superconducting transition temperature T_c of vanadium increases linearly with pressure up to 50 GPa. Pressure dependence of T_c has been measured up to 112 GPa so as to investigate to what extent such a monotonic increase in T_c would hold. T_c at 112 GPa was found to be more than three times as large as that at ambient pressure and to still increase with pressure. This value of T_c is the largest one observed in single elements.
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