Theoretical Study of Spin-Orbit Coupling in Metallic Ferromagnetism

金属铁磁性中自旋轨道耦合的理论研究

基本信息

批准号：
06640468
负责人：
ASANO Setsuro
金额：
$ 1.41万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640468/
关键词：
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 /

项目摘要

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.

自旋轨道耦合是将旋转系统固定到晶格的唯一一种相互作用，但是在3D转换金属的情况下，它太小而无法进行可靠的定量计算。在两种情况下，我们已经研究了第一原理带计算的磁各向异性能量（MAE）：稀有地球（R）和3D跃迁金属的间隙修饰的金属间的金属金属和X/CO或Fe（X = PD，PT，PT，PT，AG，AU）铁磁多磁性多层系统。在前一种情况下，GDCO_5，GDFE_ <12>，GD_2FE_ <17>的电子结构，GDFE_ <12> N和GD_2FE_ <17> N_3计算通过FLAPW方法计算，并仔细研究了R离子周围的电荷分布。氮间质离子与周围的Fe和r离子建立了牢固的键合。与FE的键合导致更大的自旋饱和力矩，但是R的粘结使R和A Crystalline Field（CF）周围具有强大的非球体电荷分布，而SMCO_5的大小。我们发现，这种大的CF是这些硝酸盐中强的单轴磁各向异性的显微镜起源。对于X/CO或FE系统，通过LMTO方法系统地计算MAE，包括自旋轨道相互作用。我们发现，在这些系统中，MAE的一般趋势是通过第一原理计算很好地解释的。还研究了CO Layr依赖性和MAE的应变依赖性的厚度。