Soft X-ray Magnetorotation Spectroscopy

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The purpose of this research is to develop an apparatus. for the (ultra-) soft X-ray Faraday-rotation measurements utilizing multilayer polarizers using synchrotron radiation (SR), to verify its usefulness for the magnetic research and to extend its ability to the measurements using laboratory light source.In the first year, we designed and constructed the Faraday-rotation apparatus. A polarizer and a analyzer are Al/YB_6 multilayers. The magnetic field was generated by the use of Sm-Co permanent magnets. The analyzer was rotated around the optical axis. The whole apparatus was accommodated in a vacuum chamber evacuated by turbo-molecular pumps. In the second year, first we made the Faraday-rotation experiments using SR at UVSOR, Institute for Molecular Science. The degree of linear polarization of the monochromatized light at BL8B1 was made higher by the use of a transmission multilayer-polarizer. The measurements were carried out on Ni (M_<2,3> ), Co (M_<2,3> ) and Co/Pt (Co - M_<2,3>, Pt - N_<6,7>) in the 50 - 70 eV region. The rotation angles obtained by the present experiment were larger than the estimated ones from MCD obtained by total-electron-yield measurements, through Kramers-Kronig an alysis. Therefore, it is concluded that the Faraday-rotation measurements are less affected by the surface conditions such as oxidization, than the MCD measurements carried out so far. Secondly, we made the light from laser-induced plasma linearly polarized by the use of a reflection multilayer-polarizer, and used the same magnet and analyzer, and obtained consistent results with those obtained using SR though the results are noisy. This is the first measurement of the soft x-ray magnetooptical effects in laboratories. We reported the results on Ni at the 12th Int. Conf. on Vacuum Ultraviolet Radiation Physics. We will make the same measurements on the other magnetic materials not measured as yet.