First-principles calculations of stability of δ-Pu–Am alloys

Landa, A.; Söderlind, Per

doi:10.1016/j.jallcom.2004.01.005

Cited by 15 publications

(15 citation statements)

References 38 publications

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“…19,20 For the total energy of random substitutional alloys, the EMTO is combined with the coherent potential approximation 21 (CPA) that also allows for the treatment of magnetic disorder. 22,23 In the present work, as well as in our previous papers, 11,12,24,25 a PM ␦-Pu was modeled within the DLM approximation. 26 This state uses a random mixture of two distinct magnetic states, namely, the spin-up and spindown configurations of the same atomic species in a system.…”

Section: Computational Detailsmentioning

confidence: 82%

First-principles elastic constants and phonons ofδ‐Pu

et al. 2004

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Elastic constants and zone-boundary phonons of ␦-plutonium have been calculated within the densityfunctional theory. The paramagnetic state of ␦-Pu is modeled by disordered magnetism utilizing either the disordered local moment or the special quasirandom structure techniques. The anomalously soft CЈ as well as a large anisotropy ratio ͑C 44 / CЈ͒ of ␦-Pu is reproduced by this theoretical model. Also the recently measured phonons for ␦-Pu compare relatively well with their theoretical counterpart at the zone boundaries.

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Section: Computational Detailsmentioning

confidence: 82%

First-principles elastic constants and phonons ofδ‐Pu

et al. 2004

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“…In the present work, as well as in our previous papers, [20][21][22][23] a paramagnetic (PM) δ-Pu was modelled within the disordered local moment (DLM) approximation [24]. In order to calculate this state, one uses a random mixture of two distinct magnetic states, namely, the spin up and spin down configurations of the same atomic species in the system.…”

Section: Computational Detailsmentioning

confidence: 99%

“…We speculate that this more stable situation in Pu 3 Am Figure 15. Lifetime broadened [35] electronic density of states for Pu and Pu 3 Am [23].…”

Section: Pu-am Systemmentioning

confidence: 99%

DENSITY-FUNCTIONAL CALCULATIONS FOR Ce, Th, AND Pu METALS AND ALLOYS

Landa¹,

Söderlind²

2004

Condens. Matter Phys.

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The phase diagrams of Ce, Th, and Pu metals have been studied by means of density-functional theory (DFT). In addition to these metals, the phase stability of Ce-Th and Pu-Am alloys has been also investigated from firstprinciples calculations. Equation-of-state (EOS) for Ce, Th, and the Ce-Th alloys has been calculated up to 1 Mbar pressure in good comparison to experimental data. Present calculations show that the Ce-Th alloys adopt a body-centered-tetragonal (bct) structure upon hydrostatic compression which is in excellent agreement with measurements. The ambient pressure phase diagram of Pu is shown to be very poorly described by traditional DFT but rather well modelled when including magnetic interactions. In particular, the anomalous δ phase of Pu is shown to be stabilized by magnetic disorder at elevated temperatures. The Pu-Am system has also been studied in a similar fashion and it is shown that this system, for about 25% Am content, becomes antiferromagnetic below about 400 K which corroborates the recent discovery of a Curie-Weiss behavior in this system.

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“…So, it is interesting to know what is happening with the electronic and magnetic structures when one is passing from δ-Pu to Am. The alloys of Pu and Am have already been studied by Landa and Söderlind, [2], with scalar-relativistic spinpolarized FPLMTO method, [3,4], and KKR-ASA method, [5,6]. They have addressed the questions of crystal stability and electronic structure for Pu-Am system with Am concentration up to 30%.…”

Section: Introductionmentioning

confidence: 99%

“…They have addressed the questions of crystal stability and electronic structure for Pu-Am system with Am concentration up to 30%. The authors of [2] have calculated the paramagnetic → antiferromagnetic transition temperature (T c ) of P u 1−x Am x alloys by the Monte Carlo technique and have found that by introducing Am into the system one could lower T c from ∼ 548K (pure Pu) to 372K (P u 0.7 Am 0.3 ).…”

Section: Introductionmentioning

confidence: 99%

Calculational Study on the Compounds Np3M, Am3M, and on the System Pu-Am

Kutepov¹

2005

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Spin-polarized relativistic density functional theory has been employed for the study of the electronic and magnetic structures for the compounds N p 3 M and Am 3 M (M = Al, Ga, In) and their comparison with plutonium's alloys P u 3 M has been made. It has been found that of the three actinides (Np, Pu, Am) only plutonium has its FCC structure essentially more stable after alloying with aforementioned elements. Apart from that, the electronic and magnetic structures for the system Pu-Am presented by three different compounds: P u 3 Am, P uAm, and P uAm 3 have been investigated. Their magnetic structures have been found to be too robust in comparison with the experimental fact that magnetism in Pu-Am system depends strongly on the percentage of the americium in the alloy. One possible explanation consists in the overestimation of the spin splitting and in the disregarding of orbital dependance of the exchange-correlation potential.

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First-principles calculations of stability of δ-Pu–Am alloys

Cited by 15 publications

References 38 publications

First-principles elastic constants and phonons ofδ‐Pu

First-principles elastic constants and phonons ofδ‐Pu

DENSITY-FUNCTIONAL CALCULATIONS FOR Ce, Th, AND Pu METALS AND ALLOYS

Calculational Study on the Compounds Np3M, Am3M, and on the System Pu-Am

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