Fragile-To-Strong Crossover In Optimized In-Sb-Te Phase-Change Supercooled Liquids

We have deposited In-doped SbxTey (x : y = 2 : 3, 1:1, 3:1, 4:1) phase-change films, and studied their physics properties like crystallization temperature, activation energy, and optical band gap. On the basis of these parameters, a balance between thermal stability and crystallization speed can be found when In content is 20 at. %. We thus further studied their crystallization kinetics using the flash differential scanning calorimetry and the generalized Mauro-Yue-Ellison-Gupta-Allan viscosity model to investigate the potential fragile-to-strong crossover (FSC) in In-20(Sb2Te3)(80), In-20(SbTe)(80), In20(Sb3Te)(80), and In-20(Sb4Te)(80) supercooled liquids. It was found that, In-20(Sb3Te)(80) has a large crossover magnitude (f) of 2.4 with a distinct FSC behavior, but its maximum crystal growth rate (U-max) of 0.047 m s(-1) is too low to satisfy the high-speed phase-change application. The crystal growth rate of In3SbTe2 (In51Sb17Te32) was found to be 0.08 m s(-1) without distinct FSC. In contrast, In-20(Sb4Te)(80) was demonstrated to have a larger Umax of 0.425 m s(-1) and a distinct FSC behavior with a f value of 2.6, which is larger than that of typical phase-change supercooled liquid Ag5.5In6.5Sb59Te29. The results strongly support that, obvious FSC is unique only in some phase-change supercooled liquids, but not a universal dynamic feature.