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Diffusionless γ⇄α phase transition in polycrystalline and single-crystal cerium.
F Decremps1, L Belhadi, D L Farber
1IMPMC, Université Pierre et Marie Curie, 75252 Paris, France.
Physical Review Letters
|March 17, 2011
Summary
The cerium gamma to alpha transition is confirmed as isomorphic, ending at a critical point. This universal behavior, similar to liquid-gas transitions, was observed in solid-state matter.
Area of Science:
- Solid-state physics
- Materials science
- Crystallography
Background:
- The cerium gamma to alpha phase transition is a complex phenomenon.
- Understanding its nature, including symmetry changes and transformation pathways, is crucial for materials science.
Purpose of the Study:
- To investigate the cerium gamma to alpha transition using advanced experimental techniques.
- To confirm the isomorphic nature of the transition and determine its critical behavior.
- To explore novel phase transformations in solid-state matter.
Main Methods:
- High-pressure, high-temperature angle-dispersive X-ray diffraction.
- Analysis of both poly- and single-crystalline cerium samples.
Main Results:
- Confirmed the isomorphic hypothesis for the cerium gamma to alpha transition.
- Identified a solid-solid critical point terminating the transition line.
- Determined a critical exponent indicating universal behavior akin to a liquid-gas transition.
- Observed an unprecedented isomorphic transition between single crystals with significant volume difference, attributed to dislocation-induced diffusionless transformation.
Conclusions:
- The cerium gamma to alpha transition exhibits universal critical behavior.
- Dislocation-induced diffusionless transformations offer new insights into solid-state phase changes.
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