The electrical resistivity and specific heat of americium metal

Müller, W.; Schenkel, R.; Schmidt, H.E.; Spirlet, J.C.; McElroy, D.L.; Hall, R.O.A.; Mortimer, Monika

doi:10.1007/bf00116197

Cited by 37 publications

(27 citation statements)

References 15 publications

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“…24(a) (Müller et al, 1978). Th, Pa, and U show lower resistivities that are closer to ordinary metals, whereas Am and Np are considerably higher.…”

Section: What We Knowmentioning

confidence: 93%

“…Resistivity measurements for Th, Pa, U, Np, α-Pu, and Am as a function of temperature are shown in Fig. 24(a) (Müller et al, 1978). The curves for Th, Pa, and U show lower resistivities with normal curvature that are similar to more ordinary metals.…”

Section: Neptuniummentioning

confidence: 98%

“…It gives information about the density of states at the Fermi level and is a direct link to the strength of electron correlations and electron localization. Results for Th (Fournier and Troc, 1985), Pa (Fournier and Troc, 1985), U (Lashley et al, 2001a), Np (Fournier and Troc, 1985), α-Pu (Elliot et al, 1964;Fournier and Troc, 1985), δ-Pu (Wick, 1980;Lashley et al, 2003;Javorsky et al, 2006), and Am (Müller et al, 1978) are shown in Fig. 24(b), where the ground-state phases are indicated by black circles.…”

Section: Neptuniummentioning

confidence: 99%

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Nature of the5fstates in actinide metals

2009

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Actinide elements produce a plethora of interesting physical behaviors due to the 5f states. This review compiles and analyzes progress in understanding of the electronic and magnetic structure of the 5f states in actinide metals. Particular interest is given to electron energy-loss spectroscopy and many-electron atomic spectral calculations, since there is now an appreciable library of core d → valence f transitions for Th, U, Np, Pu, Am, and Cm. These results are interwoven and discussed against published experimental data, such as x-ray photoemission and absorption spectroscopy, transport measurements, and electron, x-ray, and neutron diffraction, as well as theoretical results, such as density-functional theory and dynamical mean-field theory.

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“…24(a) (Müller et al, 1978). Th, Pa, and U show lower resistivities that are closer to ordinary metals, whereas Am and Np are considerably higher.…”

Section: What We Knowmentioning

confidence: 93%

Section: Neptuniummentioning

confidence: 98%

Section: Neptuniummentioning

confidence: 99%

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Nature of the5fstates in actinide metals

2009

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“…The values of the Sommerfeld coefficient for the light actinides were obtained from the following references. Thorium measurements made by Griffel and Skochdopole, 53 Pa measurements by Stewart et al 54 , low-temperature U measurements by Bader et al 55 , Np measurements by Gordon et al 30 , α-and δ-Pu by Lashley et al 49 , α'-Pu by Stewart and Elliott 52 , and Am measurements by Mueller et al 56 .…”

Section: B Specific-heat Measurementsmentioning

confidence: 99%

Absence of magnetic moments in plutonium

et al. 2005

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Many theories published in the last decade propose that either ordered or disordered local moments are present in elemental plutonium at low temperatures. We present new experimental data and review previous experimental results. None of the experiments provide any evidence for ordered or disordered magnetic moments (either static or dynamic) in plutonium at low temperatures, in either the α-or δ-phases. The experiments presented and discussed are magnetic susceptibility, electrical resistivity, NMR, specific heat, and both elastic and inelastic neutron scattering. Many recent calculations correctly predict experimentally observed atomic volumes, including that of δ-Pu. These calculations achieve observed densities by the localization of electrons, which then give rise to magnetic moments. However, localized magnetic moments have never been observed experimentally in Pu. A theory is needed that is in agreement with all the experimental observations. Two theories are discussed that might provide understanding of the ensemble of unusual properties of Pu, including the absence of experimental evidence for localized magnetic moments; an issue that has persisted for over 50 years.PACS index: 75; 75.25 +z; 75.20.En Paper to be submitted to Phys. Rev. B (11-Sept-04) I INTRODUCTIONIt has been known for many years that plutonium lies in the periodic table at a position where it is intermediate between itinerant-and localized-electron behavior. 1The elemental volumes of the 5f elements are shown in comparison to those of the elements in the 3d and 4f series in Fig. 1. The behavior of the early actinides (Th to Np) follows closely the contraction with increasing electron count that is systematically followed in all the d transition-metal series. At the beginning of the series each additional electron contributes to the cohesive energy of the solid, resulting in a decrease of volume until the shell is approximately half full. This characteristic of the early actinides, together with the absence of magnetic order, has been taken as a prima fascia case that the 5f electrons of these early actinide elements are itinerant. On the other hand, for the heavier actinide elements, there is an abrupt (at δ-Pu and Am) jump in the volume and very little change as the electron count is further increased. In comparison with the 4f elements, together with the presence of 2 ordered magnetism in Cm and the elements beyond (those that have been examined), this change in trend has been taken as evidence of localized behavior of the 5f electrons. If we accept this hypothesis, then it focuses a major interest on plutonium. Note that the volume change between α-Pu and Am is almost 50%, a staggering change in volume between two neighboring elements in the periodic table considering that the only change is to add one electron in the 5f shell. (Unlike the lanthanide elements Eu and Yb, which are both divalent in the normally trivalent lanthanide series, there is no indication of a straightforward valence change between Pu and Am)Plutoniu...

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“…Information on the lattice properties of americium is scarce and contradictory [3][4][5][6][7]. Experimental data on the thermal expansion coefficient and the bulk modulus are limited in temperature and are available only for the 243 Am.…”

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confidence: 99%