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

1.仪器仪表。我们制作了一个带有精确旋转轴的机械手、样品加热器和样品冷却器、两个Knudsen池、一个RHEED单元和一个LEED-Auger单元的小型真空室。我们还制作了一个装有一对磁体的低温恒温器，用于低温X射线测量。2.金属晶体的表征。沉积在不同金属晶体衬底上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，即Ni、Au和Cu的完美性。X射线摇摆曲线测量和X射线形貌测量结果表明，它们具有作为衬底的潜力。3. Si/Fe/Si（111）样品的制备和同步辐射测量。通过在干净的Si（111）表面上沉积Fe原子，然后退火和沉积Si盖层来制备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射线驻波法对样品进行了检验。结果表明，在此条件下生长出了理想的Fe薄膜。继续进行数据分析以精确定位界面处的原子。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，并证明了该方法适用于磁散射。我们还发展了一种新的磁电子三维分布的无模型计算方法，并将进一步利用PF和Spring-8进行实验

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