TY  - JOUR
AU  - Pries, Julian
AU  - Wei, Shuai
AU  - Wuttig, Matthias
AU  - Lucas, Pierre
TI  - Switching between Crystallization from the Glassy and the Undercooled Liquid Phase in Phase Change Material Ge 2 Sb 2 Te 5
JO  - Advanced materials
VL  - 31
IS  - 39
SN  - 1521-4095
CY  - Weinheim
PB  - Wiley-VCH
M1  - FZJ-2019-06554
SP  - 1900784 -
PY  - 2019
AB  - Controlling crystallization kinetics is key to overcome the temperature–time dilemma in phase change materials employed for data storage. While the amorphous phase must be preserved for more than 10 years at slightly above room temperature to ensure data integrity, it has to crystallize on a timescale of several nanoseconds following a moderate temperature increase to near 2/3 Tm to compete with other memory devices such as dynamic random access memory (DRAM). Here, a calorimetric demonstration that this striking variation in kinetics involves crystallization occurring either from the glassy or from the undercooled liquid state is provided. Measurements of crystallization kinetics of Ge2Sb2Te5 with heating rates spanning over six orders of magnitude reveal a fourfold decrease in Kissinger activation energy for crystallization upon the glass transition. This enables rapid crystallization above the glass transition temperature Tg. Moreover, highly unusual for glass‐forming systems, crystallization at conventional heating rates is observed more than 50 °C below Tg, where the atomic mobility should be vanishingly small.
LB  - PUB:(DE-HGF)16
C6  - pmid:31385632
UR  - <Go to ISI:>//WOS:000479612900001
DO  - DOI:10.1002/adma.201900784
UR  - https://juser.fz-juelich.de/record/867961
ER  -