scholarly journals Breakdown of Stokes-Einstein relation in the supercooled liquid state of phase change materials

2012 ◽  
Vol 249 (10) ◽  
pp. 1880-1885 ◽  
Author(s):  
G. C. Sosso ◽  
J. Behler ◽  
M. Bernasconi
Keyword(s):  
Phase Change ◽  
Liquid State ◽  
Phase Change Materials ◽  
Supercooled Liquid ◽  
Einstein Relation ◽  
Supercooled Liquid State

scholarly journals Small Atom Diffusion and Breakdown on Stokes-Einstein Relation in the Supercooled Liquid State of Zr-Ti-Cu-Ni-Be Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
U. Geyer ◽  
S. Schneider ◽  
Y. Qiu ◽  
M.-P. Macht ◽  
T. A. Tombrello ◽  
...  
Keyword(s):  
Liquid State ◽  
Diffusion Mechanism ◽  
Supercooled Liquid ◽  
Einstein Relation ◽  
Viscosity Data ◽  
Atom Diffusion ◽  
Glass Forming ◽  
Supercooled Liquid State ◽  
Liquid States ◽  
Arrhenius Expression

ABSTRACTBe diffusivity data in the bulk metallic glass forming alloys Zr41.2Ti13.8Cu12.5Ni10Be22.5 and Zr46.7Ti8.3Cu7.5Ni10Be27.5 are reported for temperatures between 530K and 710K, extending up to 80K into the supercooled liquid states of the alloys. At the glass transition temperature, Tg, a change in temperature dependence of the data is observed in both alloys, and above Tg the diffusivity increases faster with temperature than below. The data in the supercooled liquid can be described by a modified Arrhenius expression containing the communal entropy of the supercooled liquid and based on a diffusion mechanism suggested earlier. The comparison with viscosity data in the supercooled liquid state of Zr46.7Ti8.3Cu7.5Ni10Be27.5 reveals a breakdown of the Stokes- Einstein relation, whereas D(T) and η(T) follow a relation close to van den Beu-kel's. The breakdown of the Stokes- Einstein relation indicates a cooperative diffusion mechanism in the supercooled liquid state of the ZrTiCuNiBe alloys.

scholarly journals Small atom diffusion and breakdown of the Stokes–Einstein relation in the supercooled liquid state of the Zr46.7Ti8.3Cu7.5Ni10Be27.5 alloy

1996 ◽  
Vol 69 (17) ◽  
pp. 2492-2494 ◽  
Author(s):  
U. Geyer ◽  
W. L. Johnson ◽  
S. Schneider ◽  
Y. Qiu ◽  
T. A. Tombrello ◽  
...  
Keyword(s):  
Liquid State ◽  
Supercooled Liquid ◽  
Einstein Relation ◽  
Atom Diffusion ◽  
Supercooled Liquid State ◽  
Small Atom

Dynamical Heterogeneity in the Supercooled Liquid State of the Phase Change Material GeTe

2014 ◽  
Vol 118 (47) ◽  
pp. 13621-13628 ◽  
Author(s):  
Gabriele C. Sosso ◽  
Jader Colombo ◽  
Jörg Behler ◽  
Emanuela Del Gado ◽  
Marco Bernasconi
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Liquid State ◽  
Supercooled Liquid ◽  
Dynamical Heterogeneity ◽  
Supercooled Liquid State ◽  
Change Material

scholarly journals Breakdown of the Stokes-Einstein relation above the melting temperature in a liquid phase-change material

2018 ◽  
Vol 4 (11) ◽  
pp. eaat8632 ◽  
Author(s):  
Shuai Wei ◽  
Zach Evenson ◽  
Moritz Stolpe ◽  
Pierre Lucas ◽  
C. Austen Angell
Keyword(s):  
Liquid Phase ◽  
Phase Change ◽  
Melting Temperature ◽  
Phase Change Materials ◽  
Dynamic Properties ◽  
Switching Behavior ◽  
Einstein Relation ◽  
Elastic Neutron ◽  
Phase Switching ◽  
Memory Applications

The dynamic properties of liquid phase-change materials (PCMs), such as viscosity η and the atomic self-diffusion coefficientD, play an essential role in the ultrafast phase switching behavior of novel nonvolatile phase-change memory applications. To connect η toD, the Stokes-Einstein relation (SER) is commonly assumed to be valid at high temperatures near or above the melting temperatureTmand is often used for assessing liquid fragility (or crystal growth velocity) of technologically important PCMs. However, using quasi-elastic neutron scattering, we provide experimental evidence for a breakdown of the SER even at temperatures aboveTmin the high–atomic mobility state of a PCM, Ge1Sb2Te4. This implies that although viscosity may have strongly increased during cooling, diffusivity can remain high owing to early decoupling, being a favorable feature for the fast phase switching behavior of the high-fluidity PCM. We discuss the origin of the observation and propose the possible connection to a metal-semiconductor and fragile-strong transition hidden belowTm.

Micro mold filling kinetics of metallic glasses in supercooled liquid state

2013 ◽  
Vol 113 (10) ◽  
pp. 104505 ◽  
Author(s):  
J. Ma ◽  
L. S. Huo ◽  
D. Q. Zhao ◽  
W. H. Wang
Keyword(s):  
Metallic Glasses ◽  
Liquid State ◽  
Supercooled Liquid ◽  
Mold Filling ◽  
Supercooled Liquid State ◽  
Kinetics Of

scholarly journals Heat Effects Occurring in the Supercooled Liquid State and Upon Crystallization of Metallic Glasses as a Result of Thermally Activated Evolution of Their Defect Systems

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 417 ◽  
Author(s):  
Andrei Makarov ◽  
Gennadii Afonin ◽  
Yurii Mitrofanov ◽  
Nikolai Kobelev ◽  
Vitaly Khonik
Keyword(s):  
Metallic Glasses ◽  
Liquid State ◽  
Supercooled Liquid ◽  
Shear Moduli ◽  
Thermally Activated ◽  
Supercooled Liquid State ◽  
Heat Effects ◽  
Temperature Dependences ◽  
Defect System ◽  
Kinetics Of

We show that the kinetics of endothermal and exothermal effects occurring in the supercooled liquid state and upon crystallization of metallic glasses can be well reproduced using temperature dependences of their shear moduli. It is argued that the interrelation between the heat effects and shear modulus relaxation reflects thermally activated evolution of interstitial-type defect system inherited from the maternal melt.

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