Electronic and magnetic structure of thin Ni films on Co/Cu(001)
Electronic and magnetic structure of thin Ni films on Co/Cu(001)
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DOI：
10.1103/physrevb.60.12852
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发表时间：
1999-11-01
影响因子：
3.7
通讯作者：
Brookes, NB
中科院分区：
文献类型：
--
作者：
Dhesi, SS;Dürr, HA;Brookes, NB
使用圆偏振的 X 射线吸收光谱 (XAS) 研究了在超薄膜 Co 上外延生长的铁磁 Ni 薄膜的电子和磁性结构。使用高分辨率低能电子衍射验证了薄膜的生长形貌，并表明沉积在 Cu(001) 上的 Co 和 Ni 薄膜的不完全逐层生长模式。我们报告了 X 射线磁圆二色性 (XMCD) 中存在其他峰，正如配置相互作用模型所预测的那样。基态磁矩由 Ni 2p 边缘处的 XMCD 求和规则获得。对于低于 2 ML 的薄膜厚度，孔的数量和自旋极化（每个孔的自旋矩）显示逐渐减少，而轨道极化（每个孔的轨道矩）和自旋轨道相互作用显示幅度逐渐增加。块体 Ni 的 XAS 和 XMCD 中存在的 6-eV 卫星结构在亚单层覆盖范围内消失，而 L-3 和 L-3 边缘之间的“漫磁”导致的二向色性则大大增强。这些观察结果归因于杂化（电子 μ;mg）随薄膜厚度的变化，这影响了基态 d(8) 权重和 s 态自旋极化。每次旋转大幅增加的轨道力矩为定位程度提供了良好的衡量标准。结果表明，对于 Ni 薄层，波函数的局域化不会导致总磁矩的增强，相反，其值是整体值的两倍。 [S0163-1829(99)0521 1-8]。
The electronic and magnetic structure of ferromagnetic Ni films grown epitaxially on ultrathin Films of Co has been studied by x-ray-absorption spectroscopy (XAS) using circular polarization. The growth morphology of the films was verified using high-resolution low-energy electron diffraction and indicated an incomplete layer-by-layer growth mode for the Co and Ni films deposited on Cu(001). We report the presence of additional peaks in the x-ray magnetic circular dichroism (XMCD) as predicted by the configuration interaction model. The ground-state magnetic moments were obtained from the XMCD sum rules at the Ni 2p edge. For a film thickness below 2 ML the number of holes and the spin polarization (spin moment per hole) show a gradual decrease, while the orbital polarization (orbital moment per hole) and the spin-orbit interaction show a gradual increase in magnitude. The 6-eV satellite structure, which is present in the XAS and XMCD of bulk Ni, disappears for submonolayer coverages while the dichroism due to "diffuse magnetism" between the L-3 and L-3 edges is strongly enhanced. These observations are ascribed to changes in the hybridization (electronic mu;mg) as a function of film thickness, which influences the ground-state d(8) weight and the s-state spin polarization. The strongly increased orbital moment per spin provides a good measure for the degree of localization. It is shown that for Ni thin firms a localization of the wave function does not lead to an enhancement in the total magnetic moment, but, on the contrary, its value is twice as small as the bulk value. [S0163-1829(99)0521 1-8].