1995 Fiscal Year Final Research Report Summary
Theoretical Study of Spin-Orbit Coupling in Metallic Ferromagnetism
| Project/Area Number |
06640468
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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Ⅱ(磁性・金属・低温)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ASANO Setsuro The University of Tokyo, College of Arts and Sciences, Professor., 教養学部, 教授 (80013499)
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| Project Period (FY) |
1994 – 1995
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| Keywords | interstitially modifide intermetallics of Rare earth and Transition metals / spin-orbit coupling / perpendicular magnetic anisotropy / crystalline field / magnetic anisotropy / ferromagnetic multilayrs / metallic ferromagnetism / artificial superlattice |
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| Research Abstract |
The spin-orbit coupling is the only one interaction, which fixes the spin system to the lattice, but it is too small to make a reliable quantitative calculations in the case of 3d-transition metals. We have investigated the magnetic anisotropy energy (MAE) from the first-principles band calculations in the two cases : interstitially modified intermetallics of rare-earth (R) and 3d transition metals and X/Co or Fe (X=Pd, Pt, Ag, Au) ferromagnetic multilayr system. In the former case, the electronic structures of GdCo_5, GdFe_<12>, Gd_2Fe_<17>, GdFe_<12>N and Gd_2Fe_<17>N_3 were calculated by FLAPW method and the charge distribution around R ions were investigated carefully. Nitrogen interstitial ions make strong bondings with surrounding Fe and R ions. The bonding with Fe leads to a larger spin saturation moment, but that with R makes a strong aspherical charge distribution around R and a crystalline field (CF) as large as that of SmCo_5. We found that this large CF is the microscopic origin of the strong uniaxial magnetic anisotropy in these nitrides. In the case of X/Co or Fe system, the MAE were calculated systematically by the LMTO method including the spin-orbit interaction. We found that the general tendency of the MAE in these systems are well explained by first-principles calculations. The thickness of Co layr dependence and the strain dependence of the MAE were also investigated.
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