Selected Abstracts Presented at International Symposium on the Methodological Study of Phase Contrast Hard X-Ray Imaging of Nanobiological and Medical Samples with Synchrotron Radiation

It has to be noticed that diffusion or chemical reaction of adjoining layers often occur in multilayers and their characteristics are affected. Therefore the investigation of the multilayer structure in depth direction is important. Such investigation is usually made by TEM (transmission electron microscope) observing cross sections. However this method is destructive against the samples. X-ray diffraction is a nondestructive method, but it is not easy to specify the materials at interfaces and in layers by the use of this method. In this report, it is demonstrated that two kinds of soft X-ray spectroscopy are useful as nondestructive methods to investigate the multilayer structure in depth direction [1]. The first one is total electron yield (TEY) spectroscopy with angular dependence measurement. Using this method, it was found in the triple layers of LiF/Si/LiF that Si layers had a character of porous Si [2], and in triple layers of CaF2/Si/CaF2 it was found that CaF2 segregated through Si layer [3]. The second method is soft X-ray emission (SXE) spectroscopy with spectral shape analysis. Using this method, it was found in Mo/Si X-ray multilayer that heating caused diffusion or chemical reaction giving rise to deterioration of reflectance character [4]. In antiferromagnetic Fe/Si multilayers it was confirmed that there did not exist pure Si layers, but FeSi2 layers which are insulator. This suggested that the antiferromangnetic coupling is not originated from conduction electrons, but from quantum wave interference [5]. Furthermore, the application of standing wave generated in multilayers is introduced [6].