COLLAPSE OF ITINERANT ELECTRON MAGNETIC MOMENT UNDER HIGH FIELDS
| Project/Area Number |
04640333
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
WADA Hirofumi KYOTO UNIVERSITY, DEPARTMENT OF METAL SCIENCE AND TECHNOLOGY, ASSOCIATE PROFESSOR, 工学部, 助教授 (80191831)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1992: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Itinerant electron system / Metamagnetisnm / High field magnetization / Laves phase / Specific heat / Electrical resistivity / 強磁場磁化過程 |
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| Research Abstract |
One of the most important characteristics of itinerant electron magenetism is that the magnitude of magnetic moment is essentially variable with temperature, pressure and magnetic field. In this research project, first, we have studied the possibility of the collapse of itinerant electron magnetic moment by applying magnetic field using ferrimagnetic the Er_<1-x>Lu_xCo_2, system. Second, we have investigated the effects of spin fluctuations on the thermal and transport properties on Fe Laves phase compounds, in which some Fe moments disappear due to the frustration effect. The results obtained in this project are as follows.
1. In Er_<1-x>Lu_xCo_2, the Co moment is induced by the molecular field from Er moments. Since the compound is ferrimagnetic, the direction of applied field is antiparallel to that of the molecular field. This means that the applied field decreases the effective field acting upon the Co atoms, and hence the Co moment collapses under high magnetic fields, which must be observed as a metamagnetic transition. We observed a metamagmetic transition for x=0.25 at around 15T.Anomalous volume shrinkage was also detected in the magnetostriction measurements. These results clearly indicates that the Co moment collapses under high magnetic fileds.
2. The disappearance of Fe moments due to topological frustration leads to giant spin fluctuations in Hf_<1-x>Ta_xFe_2 and Sc_<1-x>Ti_xFe_2. At around the critical concentration, we observed significant enhancement of both the electronic specific heat coefficient, gamma, and the T^2 coefficient in the temperature dependence of the electrical resistivity, A.It has been found that these compounds show the Kadowaki-Woods relation. A/gamma^2=constant. The origin of this relation is also discussed on the basis of spin fluctuation theory.
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Report
(3 results)
Research Products
(14 results)
