Magnetism or bonding: A nearly periodic table of transition elements

Smith, James L.; Kmetko, E.A.

doi:10.1016/0022-5088(83)90119-4

Cited by 177 publications

(105 citation statements)

References 11 publications

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“…This lack of understanding is most apparent in plutonium, which is at the boundary of an itinerant to localized crossover of the 5f electrons that is reflected in Pu's six allotropic phases with large changes in volume between them of up to 25%. 1 Conventional electronic structure calculations do not capture this behavior, but instead predict a volume of the cubic δ-Pu phase some 30% smaller than is observed, leading to a predicted magnetically ordered ground state that experiments demonstrate is not correct. 2 Instead, plutonium is an intermediate-valence ground state involving charge fluctuations between three 5f 4 , 5f 5 , and 5f 6 electronic configurations, 3 producing an electronic structure that is arguably the most complex of all the elements.…”

Section: Introductionmentioning

confidence: 98%

Ground-state wave function of plutonium in PuSb as determined via x-ray magnetic circular dichroism

et al. 2015

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Measurements of x-ray magnetic circular dichroism (XMCD) and x-ray absorption near-edge structure (XANES) spectroscopy at the Pu M4,5 edges of the ferromagnet PuSb are reported. Using bulk magnetization measurements and a sum rule analysis of the XMCD spectra, we determine the individual orbital (µL = 2.8(1)µB/Pu) and spin moments (µS = −2.0(1)µB/Pu) of the Pu 5f electrons for the first time. Atomic multiplet calculations of the XMCD and XANES spectra reproduce well the experimental data and are consistent with the experimental value of the spin moment. These measurements of Lz and Sz are in excellent agreement with the values that have been extracted from neutron magnetic form factor measurements, and confirm the local character of the 5f electrons in PuSb. Finally, we demonstrate that a split M5 as well as a narrow M4 XMCD signal may serve as a signature of 5f electron localization in actinide compounds.

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Section: Introductionmentioning

confidence: 98%

Ground-state wave function of plutonium in PuSb as determined via x-ray magnetic circular dichroism

et al. 2015

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“…3 (Smith and Kmetko, 1983). In this diagram, the binary phase diagrams for each two neighboring elemental metals are married together.…”

Section: B Actinide Series Overviewmentioning

confidence: 99%

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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“…The R WS of elemental uranium overlaps with that of hafnium and is yet far away from the nearly constant R WS of the rare earths. Yet Hf is more a superconducting basis than a magnetic one while U sits on the "fence" between superconductivity and magnetism (Smith and Kmetko, 1983)). For a historical review of the actinides, see Moore and van der Laan (2009).…”

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confidence: 99%

Colloquium: Hidden order, superconductivity, and magnetism: The unsolved case ofURu2Si2

2011

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This Colloquium reviews the 25 year quest for understanding the continuous (2 nd ) order, meanfield-like phase transition occurring at 17.5 K in URu 2 Si 2 . Since ca. ten years the term hidden order (HO) has been coined and utilized to describe the unknown ordered state, whose origin cannot be disclosed by conventional solid-state probes, such as x-rays, neutrons, or muons. HO is able to support superconductivity at lower temperatures (Tc ≈ 1.5 K) and when magnetism is developed with increasing pressure both the HO and the superconductivity are destroyed. Other ways of probing the HO are via Rh-doping and very large magnetic fields. During the last few years a variety of advanced techniques have been tested to probe the HO state and their attempts will be summarized. A digest of recent theoretical developments is also included. It is the objective of this survey to shed additional light on the HO state and its associated phases in other materials. VII. Present State of HO 12Acknowledgments 16 References 17Figures 21 I. HISTORICAL BACKGROUNDUranium is a most intriguing element, not only in itself but also as a basis for forming a variety of compounds and alloys with unconventional or puzzling physics properties (for recent reviews, see Sechovský and Havela (1998), Santini et al. (1999), Stewart (2006)). Natural or depleted uranium, i.e. containing 99.5 percent 238 U has a * Electronic address: mydosh@physics.leidenuniv.nl † Electronic address: peter.oppeneer@physics.uu.se mild alpha radioactivity of 25 kBq/g, which allows Ubased samples to be fabricated and studied in university laboratories with a minimum of safety precautions. Following initial discoveries of unexpected superconductivity and heavy-fermion behavior in uranium-based compounds as UBe 13 (Ott et al., 1983) and UPt 3 (Stewart et al., 1984) it has become popular to synthesize uranium compounds and to cool these in search for exotic ground states. Over the past 50 or so years many conducting and insulating systems were synthesized, analyzed and structurally characterized (Sechovský and Havela, 1998;Stewart, 2001Stewart, , 2006. The usual classification of the metallic samples at low temperature is superconducting and/or magnetic or with some of the modern compounds designated as "exotic" (Pfleiderer, 2009).Why are uranium-based materials so interesting? The observed variety of unusual behaviors derive directly from the U open 5f shell. Several defining electronic structure quantities of the U f electrons are all on the same energy scale: the exchange interaction, 5f bandwidth, the spin-orbit interaction, and intra-atomic f − f Coulomb interaction. As a consequence, i) elemental uranium displays intermediate behavior between the transition metals and the rare-earths in their characteristic bandwidths, yet it generates the largest spin-orbit coupling. ii) U lies directly on the border between localized and itinerant (or overlapping) 5f wavefunctions. iii) The WignerSeitz radii R WS of comparative elements places U near the minimum between metallic and...

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Magnetism or bonding: A nearly periodic table of transition elements

Cited by 177 publications

References 11 publications

Ground-state wave function of plutonium in PuSb as determined via x-ray magnetic circular dichroism

Ground-state wave function of plutonium in PuSb as determined via x-ray magnetic circular dichroism

Nature of the5fstates in actinide metals

Colloquium: Hidden order, superconductivity, and magnetism: The unsolved case ofURu2Si2

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