1991 Fiscal Year Final Research Report Summary
Anomalous Magnetic Behavior of Samarium Compounds
| Project/Area Number |
02044120
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
YAGASAKI Katsuma College of Science, University of the Ryukyus Professor, 理学部, 教授 (70045037)
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| Co-Investigator(Kenkyū-buntansha) |
GRATZ E. Technical University of Vienna, Austria Professor, 教授
SCHMITT D. Center of National Research of Science, France Associate Professor, 助教授
MORIN P. Center of National Research of Science, France Professor, 教授
NIKI Haruo Division of General Education, University of the Ryukyus Associate Professor, 教養部, 助教授 (80145549)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Samarium / Intermetallic Compound / Giant Coercive Force / Cubic Crystalline Field / Conduction Polarization / 伝導現象 / 結晶場分裂 / sーf相互作用 |
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| Research Abstract |
This investigation has- been carried out in order to clarify origin of the giant magnetic Coercivity and to realize the state of conduction electrons and the magnetic polarization of conduction electrons of samarium compounds. The specimens of SmAgl-xlnx, SmCu ; SmZn, SmAu, SmRh and !SSMPt were prepared and the medsurements of magnetization, susceptibility, electrica. 1 resistivity, Hall resistivity and thermo-power have been done. Specimens with non-cubic structure as orthorhombic have a rather large magnetic moment of 0.9 Bohr magnetons and a very small coercive force as large as 0.5 tealers, however, specimens with cubic structure have a very small magnetic moment of 0.07 Bohr magnetons and a very large coercive force as large as 10 tib : ilers. The cubic SmAgl-xInx compounds are antiferromagnetic for x<0.2 and ferromagnetic for x>0.2 and all the compounds have second transition at Tt below the magnetic transition temperature. The coercive force of th& compounds depends on the fourth power of remanent magnetization at low temperature below Tt. It suggests that the coercive force is due to the highly anisotropic grand state of gamma-8 in the cubic crystalline field. The magnetic resistivity of these compounds takes a minimum of almost zero at x=0.2 where the magnetic ordering structure changes. This suggests that the k-f exchange integral for the antiferromagnetic compounds is negative on the contrary of the!'ferromagnetic compounds which has negative k-f integral. Thermo-power measurements revealed that the magnetic transition of SmAg compound is the first order, however, the ferromagnetic compounds in the series take place the second order transition.
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