Publication

alpha-gamma transition in metallic Ce studied by resonant x-ray spectroscopies

Marco Grioni
2004
Journal Articles

Abstract

We performed bulk-sensitive x-ray absorption (XAS) in the partial fluorescence yield (PFY) mode, and resonant x-ray emission (RXES) measurements of the solid solution Sc (7 at.%):Ce at the Ce L-3 (2p-->5d) and M-4,M-5 (3d-->4f) absorption edges. We deduce an increasing 4f-band hybridization from the gamma-phase stable at room temperature to the low-temperature alpha-Ce, consistent with the "Kondo collapse" scenario for the transition. The enhanced intrinsic resolution of PFY-XAS allows us to resolve the elusive three-peak structure predicted by theory. Thanks to the selective enhancement typical of RXES, we could estimate the small but non-negligible contribution of the f(2) configuration in the hybrid ground state, and its change in the two phases. The linear dichroism effect in the M-4,M-5 RXES spectra is consistent with the observed hybridization of 4f and conduction states.

Official source

https://infoscience.epfl.ch/entities/publication/fff6813e-f701-459e-8cc4-cd9d3535223e

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Marco Grioni
2004
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/fff6813e-f701-459e-8cc4-cd9d3535223e

About this result

Related concepts (32)

X-ray spectroscopy

X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation. When an electron from the inner shell of an atom is excited by the energy of a photon, it moves to a higher energy level. When it returns to the low energy level, the energy which it previously gained by the excitation is emitted as a photon which has a wavelength that is characteristic for the element (there could be several characteristic wavelengths per element).

X-ray fluorescence

X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by being bombarded with high-energy X-rays or gamma rays. The phenomenon is widely used for elemental analysis and chemical analysis, particularly in the investigation of metals, glass, ceramics and building materials, and for research in geochemistry, forensic science, archaeology and art objects such as paintings.

Circular dichroism

Circular dichroism (CD) is dichroism involving circularly polarized light, i.e., the differential absorption of left- and right-handed light. Left-hand circular (LHC) and right-hand circular (RHC) polarized light represent two possible spin angular momentum states for a photon, and so circular dichroism is also referred to as dichroism for spin angular momentum. This phenomenon was discovered by Jean-Baptiste Biot, Augustin Fresnel, and Aimé Cotton in the first half of the 19th century.