Understanding the link between fragile-to-strong kinetics and β-relaxation in chalcogenide glasses

Abstract

β-relaxation has been a universal behavior in various glasses with bond kinds of covalent and metallic, as well as the metavalent, which is the typical bonding of chalcogenide phase-change materials (PCMs). Recently, the fragile-to-strong (F–S) transition kinetics has been a significant feature in supercooled liquids of PCMs, to alleviate the contradiction between good thermal stability nearby glass transition temperature and fast crystallization speed around melting temperature. By analyzing the results from the measurements of powder mechanical spectroscopy and flash differential scanning calorimetry, in this work, we revealed the link between β-relaxation and F–S crystallization kinetics in GeTe-GeSe chalcogenide glass system. It was found a positive correlation between β-relaxation and F–S transition, which is accompanied by the results of resistance drift, crystallization temperature, as well as the maximum crystal growth rate. However, the GeTe component, which has large β-relaxation behavior but no F–S transition, does not obey the positive correlation because of the large activation energy of α-relaxation. These findings are expected to build a foundation and illustrate the microscopic mechanism between F–S crystallization kinetics and β-relaxation behavior in chalcogenide glasses.