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Fragile-to-strong crossover in supercooled liquid Ag-In-Sb-Te studied by ultrafast calorimetry

Fragile-to-strong crossover in supercooled liquid Ag-In-Sb-Te studied by ultrafast calorimetry
Fragile-to-strong crossover in supercooled liquid Ag-In-Sb-Te studied by ultrafast calorimetry
Phase-change random-access memory relies on the reversible crystalline-glassy phase change in chalcogenide thin films. In this application, the speed of crystallization is critical for device performance: there is a need to combine ultrafast crystallization for switching at high temperature with high resistance to crystallization for non-volatile data retention near to room temperature. In phase-change media such as nucleation-dominated Ge2Sb2Te5, these conflicting requirements are met through the highly fragile nature of the temperature dependence of the viscosity of the supercooled liquid. The present study explores, using ultrafast-heating calorimetry, the equivalent temperature dependence for the growth-dominated medium Ag-In-Sb-Te. The crystallization shows (unexpectedly) Arrhenius temperature dependence over a wide intermediate temperature range. Here it is shown that this is evidence for a fragile-to-strong crossover on cooling the liquid. Such a crossover has many consequences for the interpretation and control of phase-change kinetics in chalcogenide media, helping to understand the distinction between nucleation- and growth-dominated crystallization, and offering a route to designing improved device performance.
chalcogenide glasses; crystallization; fragile-to-strong crossover; phase-change memory; ultrafast calorimetry
1616-301X
4851-4858
Orava, J.
757b3128-2bda-4282-8317-a10f44f779f2
Hewak, D.W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Greer, A.L.
cea505bd-de1d-4a03-9871-bdd4386cb3a9
Orava, J.
757b3128-2bda-4282-8317-a10f44f779f2
Hewak, D.W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Greer, A.L.
cea505bd-de1d-4a03-9871-bdd4386cb3a9

Orava, J., Hewak, D.W. and Greer, A.L. (2015) Fragile-to-strong crossover in supercooled liquid Ag-In-Sb-Te studied by ultrafast calorimetry. Advanced Functional Materials, 25 (30), 4851-4858. (doi:10.1002/adfm.201501607).

Record type: Article

Abstract

Phase-change random-access memory relies on the reversible crystalline-glassy phase change in chalcogenide thin films. In this application, the speed of crystallization is critical for device performance: there is a need to combine ultrafast crystallization for switching at high temperature with high resistance to crystallization for non-volatile data retention near to room temperature. In phase-change media such as nucleation-dominated Ge2Sb2Te5, these conflicting requirements are met through the highly fragile nature of the temperature dependence of the viscosity of the supercooled liquid. The present study explores, using ultrafast-heating calorimetry, the equivalent temperature dependence for the growth-dominated medium Ag-In-Sb-Te. The crystallization shows (unexpectedly) Arrhenius temperature dependence over a wide intermediate temperature range. Here it is shown that this is evidence for a fragile-to-strong crossover on cooling the liquid. Such a crossover has many consequences for the interpretation and control of phase-change kinetics in chalcogenide media, helping to understand the distinction between nucleation- and growth-dominated crystallization, and offering a route to designing improved device performance.

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More information

e-pub ahead of print date: 2 July 2015
Published date: 12 August 2015
Keywords: chalcogenide glasses; crystallization; fragile-to-strong crossover; phase-change memory; ultrafast calorimetry

Identifiers

Local EPrints ID: 430980
URI: https://eprints.soton.ac.uk/id/eprint/430980
ISSN: 1616-301X
PURE UUID: 4b007ce2-b580-4772-8cab-bae7214198b9
ORCID for D.W. Hewak: ORCID iD orcid.org/0000-0002-2093-5773

Catalogue record

Date deposited: 21 May 2019 16:30
Last modified: 19 Nov 2019 01:59

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