STUDY OF RARE-EARTH ALLOYS BY X-RAY MAGNETIC BRAGG SCATTERING

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The objective of the present study is to develop practical methods of the measurements of X-ray magnetic Bragg scattering and Magnetic EXAFS and to apply them to the study of iron and rare-earth alloys. The results are summarized as follows :1. Construction of an X-ray detector and a high rate counting systemIn the present measurement, more than 10^8counts have to be accumulated in a few minutes, because the difference of the order of 10^<-4> must be detected precisely. Then it is the key point whether the high rate counting system works satisfactory or not. We have successfully constructed the system that meets the required performance, which composed of an avalanche-diode X-ray detector and a home made counting system.2. a measurement of X-ray magnetic Bragg scatteringMeasuring X-ray magnetic Bragg scattering, the X-ray magnetic form factor for Fe has been estimated. The values are in good accordance with those of the results of the band calcuration.3. measurements of magnetic EXAFS and X-ray magnetic circular dichroism (MCD)The profiles of magnetic EXAFS were measured for Fe and DyFe_2 samples. The rasults revealed that this measurement gives very useful informations reflecting the magnetic structure of the sample.The MCD profiles were also measured for 3d transition metals and the alloys of 3d transition metals and rare-earth metals. The measurements gave useful knowledge concerning the relation between an MCD profile and the band structure of magnetic electrons.