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Physical mechanism of δ-δ′-ε phase stability in plutonium
Based on first-principle calculations, we have systematically explored the nature of the elastic stability and the δ-δ′-ε phase transitions in pure Pu at high temperature. It is found that, both the electron-phonon coupling and the spin fluctuation effects tend to decrease the tetragonal elastic con...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5514108/ https://www.ncbi.nlm.nih.gov/pubmed/28717177 http://dx.doi.org/10.1038/s41598-017-06009-1 |
Sumario: | Based on first-principle calculations, we have systematically explored the nature of the elastic stability and the δ-δ′-ε phase transitions in pure Pu at high temperature. It is found that, both the electron-phonon coupling and the spin fluctuation effects tend to decrease the tetragonal elastic constant (C′) of δ-Pu, accounting for its anomalous softening at high temperature. The lattice thermal expansion together with the electron-phonon coupling can stiffen C′ of ε-Pu, promoting its mechanical stability at high temperature. The δ-ε transition is calculated to take place around 750–800 K, and is dominated by the phonon vibration. The δ′ intermediate phase is realized around 750 K mainly because of the thermal spin fluctuation. |
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