Liquid-liquid transitions, crystallization and long range fluctuations in supercooled yttrium oxide-aluminium oxide melts

Employing small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) combined with laser-heated aerodynamic levitation has enabled different transitions in supercooled yttrium oxide–aluminium oxide to be distinguished. These include liquid–liquid phase transitions as well as high temperature crystallization for different compositions. Prerequisites for avoiding crystallization in order to reveal polyamorphic phase separation in the supercooled state are established. We also show how the rise in SAXS intensity at low wavevectors can be used to identify correlation distances in long range fluctuations in high temperature melts. These distances appear to scale with melt viscosity and to extend temporarily during liquid–liquid transitions.