| Autor: |
Migliori, A., Pantea, C., Ledbetter, H., Stroe, I., Betts, J. B., Mitchell, J. N., Ramos, M., Freibert, F., Dooley, D., Harrington, S., Mielke, C. H. |
| Předmět: |
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| Zdroj: |
Journal of the Acoustical Society of America; Oct2007, Vol. 122 Issue 4, p1994-2001, 8p, 5 Charts, 4 Graphs |
| Abstrakt: |
α-plutonium’s volume-corrected polycrystal elastic moduli were measured between 18 K and the upper limit of its occurrence, near 400 K. The two independent moduli for a polycrystal—bulk and shear—behave smoothly, indicating no phase transition. Both moduli show the same 50% increase on cooling, an order of magnitude larger than in other metals. The Debye temperature obtained from low-temperature elastic moduli, 207 K, significantly exceeds most previous estimates. The Gruneisen parameter γ=5.3, obtained from the temperature dependence of the bulk modulus, is intermediate among previous estimates using other approaches, α-plutonium’s Poisson ratio ν is low: 0.18, nearly temperature independent, and its small decrease on warming opposes usual behavior. The high γ, large but equal bulk modulus and shear modulus fractional stiffening on cooling, and near-temperature-invariant ν are attributed to a single mechanism: 5-f electron localization—delocalization. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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