Levitation Methods for Structural and Dynamical Studies of Liquids at High Temperatures

Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany

Abstract

In recent years, levitation methods have been increasingly used to study the atomic structure and dynamics of high-temperature liquids, in particular metallic melts. These methods provide a containerless and, consequently, high-purity sample environment. No corrections for signals due to a crucible need to be made, and deep undercoolings of the liquid become possible, reducing the effect of thermal fluctuations. On the other hand, the sample position and, hence, the scattering geometry is not fixed and the free sample surface exhibits capillary waves. Nevertheless, the combination of levitation techniques with x-ray or neutron sources has proven to be possible and successfull. This paper reviews the progress made in this field during the last 10 years or so. It discusses the different levitation techniques: aerodynamic, electromagnetic, electrostatic, as well as the applied spectroscopic techniques: x-ray and neutron diffraction, x-ray absorption and quasi-elastic neutron diffraction. Some recent results are also highlighted.