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

点击翻译按钮获取中文摘要

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