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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
9.1K
Incommensurate systems as model compounds for disorder revealing low-temperature glasslike behavior.
G Reményi1,2, S Sahling1,2,3, K Biljaković1,2,4
1Université Grenoble Alpes, Institut Néel F-38042 Grenoble, France.
Physical Review Letters
|May 30, 2015
Summary
Specific heat anomalies in incommensurate crystals mirror those in glasses. These low-temperature features, including upturns and bumps, arise from the crystal
Area of Science:
- Condensed Matter Physics
- Materials Science
- Thermodynamics
Background:
- Amorphous and glass materials exhibit unique low-temperature specific heat anomalies, deviating from the Debye T^3 law.
- Incommensurately modulated crystals possess broken translational periodicity, a structural characteristic potentially influencing their thermodynamic properties.
- Understanding the origins of low-temperature anomalies in diverse materials is crucial for fundamental physics and material design.
Purpose of the Study:
- To investigate the low-temperature specific heat behavior of incommensurately modulated crystals.
- To identify the microscopic origins of observed specific heat anomalies in these materials.
- To explore the relationship between the dynamics of incommensurate structures and the anomalous properties of glasses.
Main Methods:
- Experimental measurement of specific heat (C_p) as a function of temperature (T) for incommensurately modulated crystals.
- Analysis of the specific heat data, focusing on deviations from the Debye limit (constant C_p(T)/T^3).
- Theoretical interpretation linking observed anomalies to gapped phase and amplitude modes of the incommensurate structure.
Main Results:
- Incommensurately modulated crystals exhibit specific heat features similar to amorphous and glass materials at low temperatures.
- An upturn in specific heat below 1 K and a broad bump around 10 K were observed, exceeding the Debye limit.
- These anomalies are directly attributed to the gapped phase and amplitude modes characteristic of the incommensurate structure.
Conclusions:
- The low-energy dynamics of incommensurate systems provide a simplified model for understanding the complex interactions in glasses.
- The study establishes a direct link between the structural properties of incommensurate crystals and their low-temperature thermodynamic anomalies.
- These findings offer new insights into the universal nature of low-temperature behavior in disordered and complex crystalline systems.
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