Study of Undercooled Melt and Solidification Using Synchrotron Radiation and Electrostatic Levitation Technique

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Our project, which is the realization of a compact electrostatic levitator for the measurements using synchrotron radiation and measurements of x-ray diffraction, Compton scattering and high resolution x-ray inelastic scattering at Spring-8 has been fulfilled nearly as planned.(1) X-ray diffraction:High energy x-ray diffraction profiles have been precisely measured for the melts and undercooled melts of Zr, Si and Ba-Ge compunds using electrostatic levitation technique. And their structures were analyzed partly with Monte Carlo simulation.For the melt of icosahedral ALPdMn alloy, the first peak in low angle region has been clearly detected for the first time in the x-ray diffraction profile, which confirms the existence of order structure in the scale of 0.35nm in the melt.(2) Compton scattering and high resolution x-ray inelastic scattering:Compton scattering profiles for Si melt was measured at BLO8W in Spring-8. The analyses of the obtained momentum distribution of valence electrons have demonstrated the existence of covalent bonds for the first time.High resolution x-ray inelastic scattering profiles were measured for Si melt and Si undercooled melt of 1517K, and dynamic structure factor has found clearly different between them.This is the first case in the world that a profile of Compton scattering and/or high resolution x-ray inelastic scattering is successfully measured. The present studies are to be pioneering work that shows it is really possible to study dynamics and electronic structures of high temperature melt and undercooled melt.