Structural analysis of Fe/Ni(001) films by photoelectron diffraction
Structural analysis of Fe/Ni(001) films by photoelectron diffraction
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Fe/Ni(001)薄膜的光电子衍射结构分析
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
S. Nannarone
中科院分区：
文献类型：
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作者：
G. Gazzadi;P. Luches;A. D. Bona;L. Marassi;L. Pasquali;S. Valeri;S. Nannarone
用光电子衍射法在0-14ML覆盖范围内研究了外延生长在Ni~001！上的Fe薄膜的结构。在前向散射区域。用多次散射的方法对覆盖率分别为3和7毫升的铁膜进行了定量分析。对3-ML数据的分析表明，生长不是逐层的，而是通过岛核发生的，从假象的fcc相到bcc相的转变位于生长的早期阶段。实际上，最佳拟合是通过对2ML bcc~110！/3ML fcc~001！Fe膜具有BCĉ111和I面心立方^110的平面取向。Bcc区、bcc层与fcc层之间和fcc区的层间距分别为2.05、2.0160.03和1.85 60.03；最适合平面内的最近邻居~n-n！距离为2.49 60.02？，与镍衬底的距离一致。分析7-ML数据a 4 ML bcc~110！/3 ML fcc~001！采用薄膜，只改变体心立方区域的拟合参数。层间距为2.04 60.04？，平面n-n距离为2.47？60.01？时，得到了最佳拟合。在14毫升时，在94°方位角范围内收集的局部放电图案显示出围绕@110#衬底方向的对称性，这可以用4bcc~110！满足BCC^111和I FCC^110&对齐的域。
The structure of Fe films, epitaxially grown on Ni ~001!, has been studied in the 0–14 ML coverage range by means of photoelectron diffraction ~PD! in the forward scattering regime. Quantitative analysis by a multiple scattering approach has been performed on Fe films at a coverage of 3 and 7 ML. Analysis of the 3-ML data showed that growth was not layer-by-layer but rather occurred through islands nucleation and that transition from the pseudomorphic fcc to the bcc phase was located in this early stage of growth. In fact, best fit was obtained by calculations o n a 2 ML bcc~110!/3 ML fcc~001! Fe film with the bcĉ111&i fcc^110& in-plane orientation. Interlayer spacings of 2.05 60.06 Å, 2.0160.03 Å, and 1.85 60.03 Å were found in the bcc region, between bcc and fcc layers and in the fcc region, respectively. Best-fit in-plane nearest-neighbors ~n-n! distance was 2.49 60.02 Å, in registry with that of the Ni substrate. To analyze the 7-ML dat a 4 ML bcc~110!/3 ML fcc~001! film was employed, varying the fitting parameters in the bcc region only. Best fit was obtained for an interlayer spacing of 2.04 60.04 Å and in plane n-n distance of 2.47 60.01 Å. At 14 ML the PD pattern collected over a 94° azimuthal range displayed symmetry around the @110# substrate direction, which was explained by the equipopulation of the 4 bcc ~110! domains satisfying the bcc ^111&i fcc^110& alignment.