Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry
Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry
Differential scanning calorimetry (DSC) is widely used to study the stability of amorphous solids, characterizing the kinetics of crystallization close to the glass-transition temperature Tg. We apply ultrafast DSC to the phase-change material Ge2Sb2Te5 (GST) and show that if the range of heating rates is extended to more than 104 K s-1, the analysis can cover a wider temperature range, up to the point where the crystal growth rate approaches its maximum. The growth rates that can be characterized are some four orders of magnitude higher than in conventional DSC, reaching values relevant for the application of GST as a data-storage medium. The kinetic coefficient for crystal growth has a strongly non-Arrhenius temperature dependence, revealing that supercooled liquid GST has a high fragility. Near Tg there is evidence for decoupling of the crystal-growth kinetics from viscous flow, matching the behaviour for a fragile liquid suggested by studies on oxide and organic systems.
279-283
Orava, J.
757b3128-2bda-4282-8317-a10f44f779f2
Greer, A.L.
cea505bd-de1d-4a03-9871-bdd4386cb3a9
Gholipour, B.
c17bd62d-9df6-40e6-bc42-65272d97e559
Hewak, D.W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Smith, C.E.
07421867-27eb-4b9b-b2fd-f6d64c27ef86
18 March 2012
Orava, J.
757b3128-2bda-4282-8317-a10f44f779f2
Greer, A.L.
cea505bd-de1d-4a03-9871-bdd4386cb3a9
Gholipour, B.
c17bd62d-9df6-40e6-bc42-65272d97e559
Hewak, D.W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Smith, C.E.
07421867-27eb-4b9b-b2fd-f6d64c27ef86
Orava, J., Greer, A.L., Gholipour, B., Hewak, D.W. and Smith, C.E.
(2012)
Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry.
Nature Materials, 11 (4), .
(doi:10.1038/NMAT3275).
Abstract
Differential scanning calorimetry (DSC) is widely used to study the stability of amorphous solids, characterizing the kinetics of crystallization close to the glass-transition temperature Tg. We apply ultrafast DSC to the phase-change material Ge2Sb2Te5 (GST) and show that if the range of heating rates is extended to more than 104 K s-1, the analysis can cover a wider temperature range, up to the point where the crystal growth rate approaches its maximum. The growth rates that can be characterized are some four orders of magnitude higher than in conventional DSC, reaching values relevant for the application of GST as a data-storage medium. The kinetic coefficient for crystal growth has a strongly non-Arrhenius temperature dependence, revealing that supercooled liquid GST has a high fragility. Near Tg there is evidence for decoupling of the crystal-growth kinetics from viscous flow, matching the behaviour for a fragile liquid suggested by studies on oxide and organic systems.
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Published date: 18 March 2012
Organisations:
Optoelectronics Research Centre
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Local EPrints ID: 336493
URI: http://eprints.soton.ac.uk/id/eprint/336493
ISSN: 1476-1122
PURE UUID: f4f95bd6-853f-401b-b997-3f54fd4a40f3
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Date deposited: 28 Mar 2012 10:34
Last modified: 14 Mar 2024 10:43
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Author:
J. Orava
Author:
A.L. Greer
Author:
B. Gholipour
Author:
C.E. Smith
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