1997 Fiscal Year Final Research Report Summary
Theoretical Study on Spin and Orbital Moments in Actinide Magnets
| Project/Area Number |
08640461
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
JO Takeo Faculty of Science, HIROSHIM UNIVERSITY Professor, 理学部, 教授 (20093487)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Arata Faculty of Science, HIROSHIMA UNIVERSITY Research Associate, 理学部, 助手 (70253052)
OGUCHI Tamio Faculty of Science, HIROSHIMA UNIVERSITY Professor, 理学部, 教授 (90253054)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Actinide / Uranium compound / Orbital magnetic moment / Hartree-Fock approximation / LDA / Magnetic circular dichroism / FeO / CoO |
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| Research Abstract |
We have extended the Hartree-Fock (HF) calculation of the 5f orbital and spin moments (M_<orb> and M_<spin>, respectively) to NaCl-type ferromagnet USe and UTe in addition to US on the basis of an extended Hubbard model, where the 5f, 6d and 7s orbits of U atom and the 3s, 3p ones of S atom are included and the intraatomic multipole 5f-5f interaction is taken into account. We determined the parameters of transfer integral by using the LDA-FLAPW calculation in the paramagnetic state without spin-orbit interaction. The Slater integral except F^0 representing the 5f-5f interaction is determined by HF calculation or analyzes of high-energy spectroscopies. We determine F^0 so as to obtain an agreement between the calculation and the experiment for the total 5f moment. The obtained M_<spin> and M_<orb > are antiparallel with each other and the ratio M_<orb>/M_<2spin> is - 2.1, which is in agreement with experimental results. We determine self-consistently the expectation values of 14 number operators and 91 (= _<14>C_2) off-diagonal operators of the 5f state. The includion of the latter is found to be important to estimate the magnitude of spin dipole.
We have also performed the HF calculation of M_<spin> and M_<orb> of the second-type antiferromagnets CoO and FeO with taking into account the full 3d orbits and multipole interaction and the O 2p orbits. The calculated M_<orb> of both systems is found to be - 1mu_B, which has been pointed out in a single-ion model. For CoO,we found as a HF solution a non-collinear magnetic structure in addition to a collinear structure, both of which are suggested as candidates by the neutron diffraction.
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Research Products
(10 results)
