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Isothermal Annealing Effects on $β$-Relaxations and Crystallization Behaviors in Amorphous GeTe
Authors:
Arune Makareviciute,
Qun Yang,
Tomoki Fujita,
Oliver Gross,
Nico Neuber,
Maximilian Frey,
Jens Moesgaard,
Cecile Chaxel,
Julian Pries,
Mads Ry Vogel Jørgensen,
Frederik Holm Gjørup,
Matthias Wuttig,
Hai-bin Yu,
Jiangjing Wang,
Shuai Wei
Abstract:
A secondary $β$-relaxation process is often the dominant source of atomic dynamics below $T_\mathrm{g}$ in many glass forming systems. Recent studies reported the presence of $β$-relaxations in amorphous phase-change materials (PCMs) and showed that suppressing the $β$-relaxation via annealing in Ge$_{15}$Sb$_{85}$ can effectively slow down its crystallization kinetics. Yet, when Sb is replaced by…
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A secondary $β$-relaxation process is often the dominant source of atomic dynamics below $T_\mathrm{g}$ in many glass forming systems. Recent studies reported the presence of $β$-relaxations in amorphous phase-change materials (PCMs) and showed that suppressing the $β$-relaxation via annealing in Ge$_{15}$Sb$_{85}$ can effectively slow down its crystallization kinetics. Yet, when Sb is replaced by Te, similar annealing protocol has little effect on the Te-rich alloy Ge$_{15}$Te$_{85}$. Here, we investigate amorphous GeTe that is a Sb-free PCM, but with faster crystallization kinetics than Ge$_{15}$Te$_{85}$. Using powder mechanical dynamic spectroscopy, we observe a clear reduction of the excess-wing in the loss modulus upon isothermal annealing, indicating a suppression of its $β$-relaxation. Ultrafast calorimetric analysis and time-resolved optical reflectivity measurements show that, whereas as-deposited GeTe exhibit stochastic crystallization behaviors, annealed samples crystallize more slowly with reduced stochasticity. Synchrotron X-ray scattering experiments reveal reinforced Peierls-like distortions in the amorphous structure after annealing, and demonstrate that, even if annealing introduces nucleation sites, it nonetheless slows down crystallization kinetics. These finding suggests that, in annealed GeTe, crystallization is limited by crystal growth rate, which is retarded through the suppression of $β$-relaxation.
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Submitted 15 October, 2025;
originally announced October 2025.
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Disentangling structural and kinetic components of the α-relaxation in supercooled metallic liquids
Authors:
Nico Neuber,
Oliver Gross,
Maximilian Frey,
Benedikt Bochtler,
Alexander Kuball,
Simon Hechler,
Fan Yang,
Eloi Pineda,
Fabian Westermeier,
Michael Sprung,
Isabella Gallino,
Ralf Busch,
Beatrice Ruta
Abstract:
The particle motion associated to the α-relaxation in supercooled liquids is still challenging scientists due to its difficulty to be probed experimentally. By combining synchrotron techniques, we found the existence of microscopic structure-dynamics relationships in Pt42.5Cu27Ni9.5P21 and Pd42.5Cu27Ni9.5P21 liquids which allows us to disentangle structural and kinetic contributions to the α-proce…
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The particle motion associated to the α-relaxation in supercooled liquids is still challenging scientists due to its difficulty to be probed experimentally. By combining synchrotron techniques, we found the existence of microscopic structure-dynamics relationships in Pt42.5Cu27Ni9.5P21 and Pd42.5Cu27Ni9.5P21 liquids which allows us to disentangle structural and kinetic contributions to the α-process. While the two alloys show similar kinetic fragilities, their structural fragilities differ and correlate with the temperature dependence of the stretching parameter describing the decay of the density fluctuations. This implies that the evolution of dynamical heterogeneities in supercooled alloys is determined by the rigidity of the melt structure. We find also that the atomic motion not only reflects the topological order but also the chemical short-range order, which can lead to a surprising slowdown of the α-process at the mesoscopic length scale. These results will contribute to the comprehension of the glass transition, which is still missing.
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Submitted 20 September, 2022;
originally announced September 2022.
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Wave vector dependence of the dynamics in supercooled metallic liquids
Authors:
B. Ruta,
S. Hechler,
N. Neuber,
D. Orsi,
L. Cristofolini,
O. Gross,
B. Bochtler,
M. Frey,
A. Kuball,
S. S. Riegler,
M. Stolpe,
Z. Evenson,
C. Gutt,
F. Westermeier,
R. Busch,
I. Gallino
Abstract:
We present a detailed investigation of the wave vector dependence of collective atomic motion in Au49Cu26.9Si16.3Ag5.5Pd2.3 and Pd42.5Cu27Ni9.5P21 supercooled liquids close to the glass transition temperature. Using x-ray photon correlation spectroscopy in a precedent uncovered spatial range of only few interatomic distances, we show that the microscopic structural relaxation process follows in ph…
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We present a detailed investigation of the wave vector dependence of collective atomic motion in Au49Cu26.9Si16.3Ag5.5Pd2.3 and Pd42.5Cu27Ni9.5P21 supercooled liquids close to the glass transition temperature. Using x-ray photon correlation spectroscopy in a precedent uncovered spatial range of only few interatomic distances, we show that the microscopic structural relaxation process follows in phase the structure with a marked slowing down at the main average inter-particle distance. This behavior is accompanied by dramatic changes in the shape of the intermediate scattering functions which suggest the presence of large dynamical heterogeneities at length-scales corresponding to few particle diameters. A ballistic-like mechanism of particle motion seems to govern the structural relaxation of the two systems in the highly viscous phase, likely associated to hopping of caged particles in agreement with theoretical studies.
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Submitted 28 August, 2020; v1 submitted 3 March, 2020;
originally announced March 2020.
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Liquid-liquid transition revealed by quasi-static cooling of an ultra-viscous metallic liquid
Authors:
S. Hechler,
B. Ruta,
M. Stolpe,
E. Pineda,
Z. Evenson,
O. Gross,
W. Hembree,
A. Bernasconi,
R. Busch,
I. Gallino
Abstract:
Temperature-driven polyamorphism has been reported in various supercooled liquids and glasses. The dynamical and structural routes followed by the system during such crossovers are however not universal and appear to be related to intrinsic kinetic properties of the liquid. By combining x-ray photon correlation spectroscopy and high energy x-ray diffraction, we have followed the collective atomic…
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Temperature-driven polyamorphism has been reported in various supercooled liquids and glasses. The dynamical and structural routes followed by the system during such crossovers are however not universal and appear to be related to intrinsic kinetic properties of the liquid. By combining x-ray photon correlation spectroscopy and high energy x-ray diffraction, we have followed the collective atomic motion and structural changes during quasi-static cooling of the Au49Cu26.9Si16.3Ag5.5Pd2.3 metallic glass-former. Due to this ultra-slow thermal protocol, the glass transition temperature is lowered far enough to reveal a liquid-liquid crossover in the ultra-viscous supercooled phase. This transition is usually hidden by vitrification and leads to a strong liquid characterized by increasing correlation at the medium range.
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Submitted 21 April, 2017;
originally announced April 2017.