Theoretical Study on Spin and Orbital Moments in Actinide Magnets

锕系磁体自旋矩和轨道矩的理论研究

• 批准号: 08640461
• 负责人: JO Takeo
• 金额: $ 1.34万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640461/
• 关键词: Actinide; Uranium compound; Orbital magnetic moment; Hartree-Fock approximation; LDA; Magnetic circular dichroism; FeO; CoO; ハートレー・フォックス近似; アンダーソン模型; 配置間相互作用

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.

本文在扩展的Hubbard模型的基础上，将Hartree-Fock（HF）计算方法推广<orb><spin>到NaCl型铁磁体USe和UTe，其中包括U原子的5 f，6d和7s轨道以及S原子的3s，3 p轨道，并考虑了原子内多极5 f-5 f相互作用.利用LDA-FLAPW方法计算了无自旋轨道相互作用的顺磁态下的转移积分参数。除F^0代表5 f-5 f相互作用外，其它斯莱特积分均由HF计算或高能光谱分析确定。我们确定F^0是为了使总的5 f矩的计算值与实验值一致。得到的<spin>M_1和M_2<orb >是反平行的，<orb>M_1/M_2<2spin>为-2.1，与实验结果一致。我们自洽地确定了5 f态的14个数算符和91个（= <14>C_2）非对角算符的期望值。我们还计算了<spin><orb>第二类反铁磁体CoO和FeO的M_1和M_2，并考虑了全三维轨道和多极相互作用以及O ~（2 p）轨道。两个体系的计算M_2<orb>均为-1mu_B，这在单离子模型中已被指出。对于CoO，我们发现作为HF溶液的非共线的磁性结构，除了共线结构，这两者都建议作为候选人的中子衍射。

项目成果

A.Tanaka: "Spectral Functions of Elecctron-Doped Cu-Dxide Cluster Model Including Full Multiplet" Physica B. 237-238. 385-387 (1997)

A.Tanaka：“包括全多重态的电子掺杂铜氧化物团簇模型的光谱函数”Physica B.237-238。

K. Iwashita: "Orbital and Spin Magnetic Moments of Tpt_3 (T=V, Cr, Mn, Fe and Co)" Physical Revicus B. 54. 1159-1162 (1996)

K. Iwashita：“Tpt_3 的轨道和自旋磁矩（T=V、Cr、Mn、Fe 和 Co）”Physical Revicus B. 54. 1159-1162 (1996)

T.Jo: "Magnetic Circulnr Diohroism of 3d-2p and 4d-2p X-Ray Enrission in Rare Ecnths" Journal of the Physical Society of Japan. (発表予定). (1998)

T.Jo：“Rare Ecnths 中 3d-2p 和 4d-2p X 射线的磁环二色性”，日本物理学会杂志（即将出版）。

T. Jo: "The 3d-4f Exchange Interaction X-Ray 2nd Order Optical Processes and MCD Spin Sum Rule in Rase Earths" Journal of Electron Spectroscopy and Related. (発表予定). (1997)

T. Jo：“Rase Earths 中的 3d-4f 交换相互作用 X 射线二阶光学过程和 MCD 自旋和规则”《电子光谱学及相关杂志》（即将出版）。

T.Jo: "The3d-4f Exchange Interaction, X-Rey 2nd Order Optical Processes and MCD Spin Sum Rule in Rare Earths" Journal of Electron Spectroscopy and Related Phenomena. 86. 73-82 (1997)

T.Jo：“稀土中的 3d-4f 交换相互作用、X-Rey 二阶光学过程和 MCD 自旋和规则”《电子能谱和相关现象杂志》。