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Atomic Magnetic State and Theory of X-Ray Spectroscopy in d and f Electron Systems

d 和 f 电子系统中的原子磁态和 X 射线能谱理论

基本信息

批准号：
10640348
负责人：
JO Takeo
金额：
$ 1.22万
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：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640348/
关键词：
orbital moment spin moment x-ray absorption magnetic circular dichroism multipole interaction orbital orderingt Co LaMnOィイD23ィエD2 X線発光双極子遷移総和則

项目摘要

By using sum rules to relate the integrated intensity of magnetic circular dichroism (MCD) spectrum in core-to-valence x-ray absorption and the atomic spin and orbital magnetic moments, the atomic orbital moment (MィイD20ィエD2) has been measured extensively in many transition metal multilayers and has been compared with that for bulk systems. We discuss the atomic environment dependence of MィイD20ィエD2 of various Co superlattices in Pd and Cu matixes on the basis of the tight-binding model including the d-d multipole interaction within the Hartree-Fock approximation In Pd matrix due to a large lattice constant, MィイD20ィエD2 of Co is increased to twice or so of the bulk value and it is rather insensitive to the atomic environment. In Cu matrix, on the other hand, since the effective Co-Cu 3d hybridization is much smaller than the Co-Co one, MィイD20ィエD2 of Co is found to be strongly dependent on the atomic environment and can be comparable to its spin counterpart.We discussed the relation between the "antiferromagnetic" Mn 3d orbital ordering in LaMnOィイD23ィエD2 and the linear dichroism in MnLィイD22,3ィエD2, absorption on the basis of the single-ion model taking into account the crystal field and the intraatomic multipole interaction. Although the recent resonant x-ray scattering at Mn K edge is expected as a method of directly observing the orbital ordering there have been controversies that it only observe the distortion of MnOィイD26ィエD2 cluster. The present study shows that the multiplet structure in x-ray absorption spectrum can play a role as a fingerprint to identify the type of orbital ordering.

利用求和规则将核价X射线吸收中磁性圆二色谱的积分强度与原子的自旋磁矩和轨道磁矩联系起来，在许多过渡金属多层膜中测量了原子轨道矩(MィイD20ィエD2)，并与大块体系的轨道矩进行了比较。本文在紧束缚模型的基础上讨论了不同Co超晶格的MィイD20ィエD2对原子环境的依赖关系，包括Pd矩阵中的d-d多极相互作用，由于较大的晶格常数，Co的MィイD20ィエD2增加到体积值的两倍左右，对原子环境不敏感。另一方面，由于有效的Co-Cu3D杂化比Co-Co杂化小得多，发现Co的MィイD20ィエD2强烈依赖于原子环境，可以与其自旋相当。我们在考虑晶场和原子内多极相互作用的单离子模型的基础上，讨论了LaMnOィイD23ィエD2中的反铁磁性Mn3D轨道有序与ィイD22，3ィエD2中的线性二色性、吸收之间的关系。尽管最近在MnK边的共振X射线散射被认为是一种直接观察轨道有序性的方法，但它只观察到MnOィイD26ィエD2团簇的扭曲，这一点一直存在争议。本研究表明，X射线吸收光谱中的多重态结构可以作为识别轨道有序化类型的指纹。