Study of magnetic stuctures of surfaces and interfaces by X-ray diffraction

1. 仪表。我们制作了一个超高真空室，配备了一个具有精确旋转轴的机械手，一个样品加热器和一个样品冷却器，两个Knudsen细胞，一个RHEED单元和一个LEED-Auger单元。我们还制作了一个低温恒温器，配有一对磁铁，用于在低温下进行x射线测量。金属晶体的表征。在不同金属的晶体基底上沉积的金属薄膜中出现了许多有趣的磁性结构。因此，我们研究了用于衬底的典型金属晶体的可完善性，即Ni， Au和Cu。x射线-岩石曲线测量和x射线形貌的结果验证了它们可以作为基底的潜力。Si/Fe/Si（111）样品的制备及同步辐射测量。将铁原子沉积在干净的Si（111）表面，然后退火并沉积Si帽层，制成Si/Fe/Si（111）样品。在光子工厂（PF）用反射率法、衍射异常精细结构法和x射线驻波法检测样品。结果表明，生长出了理想的铁薄膜。继续进行数据分析，以精确地定位界面上的原子。理论。建立了一种计算简单原子层x射线散射振幅绝对值的方法，并证明该方法适用于磁散射。我们还开发了一种新的无模型计算磁性电子三维分布的方法。利用PF和Spring-8进行进一步的实验研究

1. Instrumentation. We made an ultrahigh vacuum chamber equipped with a manipulator which has precise rotation axes, a sample heater and a sample cooler, two Knudsen cells, an RHEED unit and a LEED-Auger unit. We also made a cryostat equipped with a pair of magnets for X-ray measurement at low temperature.2.Characterization of metallic crystals. A lot of interesting magnetic structures appear in metallic thin films deposited on crystal substrates of different metals. Therefore we examined perfectibility of typical metallic crystals used for substrates, i.e. Ni, Au and Cu. The results of X-ray-rocking-curve measurement and X-ray topography verify that they canbe potentially used as substrates.3.Prepartion of a Si/Fe/Si(111) sample and measurement by synchrotron radiation. A Si/Fe/Si(111) sample was made by deposition of Fe atoms on a clean Si(111) surface followed by annealing and deposition of a Si cap layer. The sample was examined at Photon Factory (PF) by reflectivity method, diffraction-anomalous-fine-structure method and X-ray-standing-wave method. The result shows that an ideal Fe thin film is grown. Data analysis is continued to locate atoms at the interface precisely.4. Theory. We established a calculation method to determine an absolute value of X-ray scattering amplitude from a simple atomic layer and showed it is applicable to magnetic scattering. We also developed a new method of modelfree calculation for 3D distribution of magnetic electrons.Farther experiments using PF and Spring-8 are intended to develop this study