TY  - JOUR
AU  - Pries, Julian
AU  - Weber, Hans
AU  - Benke-Jacob, Julia
AU  - Kaban, Ivan
AU  - Wei, Shuai
AU  - Wuttig, Matthias
AU  - Lucas, Pierre
TI  - Fragile-to-Strong Transition in Phase-Change Material Ge3Sb6Te5
JO  - Advanced functional materials
VL  - 32
IS  - 31
SN  - 1057-9257
CY  - Weinheim
PB  - Wiley-VCH
M1  - FZJ-2022-02238
SP  - 2202714 -
PY  - 2022
AB  - Chalcogenide phase-change materials combine a remarkable set of properties that makes them promising candidates for future non-volatile memory applications. Binary data storage exploits the high contrast in electrical and optical properties between the covalent amorphous and metavalent crystalline phase. Here the authors perform an analysis of the liquid phase kinetics of the phase-change material Ge3Sb6Te5, which is the key to ultrafast switching speeds. By employing four experimental techniques, the viscosity is measured over sixteen orders of magnitude despite its propensity for fast crystallization. These measurements reveal that the liquid undergoes a transition in viscosity–temperature dependence associated with a liquid–liquid phase transition. The system exhibits a shallow viscosity change with temperature near the glass transition which stabilizes the memory cells in the amorphous state and which limits the severity of relaxation processes. Meanwhile, when heated during the writing process, the fragility increases to more than double, causing the viscosity to drop rapidly enabling a nanosecond crystallization speed. This change in viscosity–temperature dependence is highly unusual among glass forming liquids and is reminiscent of the behavior of water. This viscosity transition is also key to the technological success of phase-change materials for computer memory applications.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000794043200001
DO  - DOI:10.1002/adfm.202202714
UR  - https://juser.fz-juelich.de/record/907839
ER  -