X-ray absorption studies of RRhAl (R ¼ La and Ce) compounds
TL;DR: In this paper, X-ray absorption spectra at the L 3 (2 p → 5 d ) and M 5,4 (3 d → 4 f ) edges of Ce and La in the above ternary intermetallic compounds were reported.
Abstract: The compound CeRhAl is neither magnetically ordered nor superconducting down to 2 K and LaRhAl is superconducting at 2.4 K . We report X-ray absorption spectra at the L 3 (2 p →5 d ) and M 5,4 (3 d →4 f ) edges of Ce and La in the above ternary intermetallic compounds. Based on this spectroscopic investigation, it is found that Ce shows mixed valent nature and La is in trivalent state.
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TL;DR: In this paper, the authors present a review of all the important results obtained in this family, particularly in the last few years, by means of a variety of techniques/measurements such as X-ray diffraction, neutron diffraction and NQR.
216 citations
TL;DR: Lai et al. as discussed by the authors investigated the structural, thermodynamic, and electronic transport properties of the isoelectronic chemical substitution series Ce(Pd1-xNix)2P2, where a possible ferromagnetic quantum critical point is uncovered in the temperature-concentration (T-x) phase diagram.
Abstract: Author(s): Lai, Y; Bone, SE; Minasian, S; Ferrier, MG; Lezama-Pacheco, J; Mocko, V; Ditter, AS; Kozimor, SA; Seidler, GT; Nelson, WL; Chiu, YC; Huang, K; Potter, W; Graf, D; Albrecht-Schmitt, TE; Baumbach, RE | Abstract: An investigation of the structural, thermodynamic, and electronic transport properties of the isoelectronic chemical substitution series Ce(Pd1-xNix)2P2 is reported, where a possible ferromagnetic quantum critical point is uncovered in the temperature-concentration (T-x) phase diagram. This behavior results from the simultaneous contraction of the unit cell volume, which tunes the relative strengths of the Kondo and Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions, and the introduction of disorder through alloying. Near the critical region at xcr≈ 0.7, the rate of contraction of the unit cell volume strengthens, indicating that the cerium f valence crosses over from trivalent to a noninteger value. Consistent with this picture, x-ray absorption spectroscopy measurements reveal that while CePd2P2 has a purely trivalent cerium f state, CeNi2P2 has a small (l10 %) tetravalent contribution. In a broad region around xcr, there is a breakdown of Fermi-liquid temperature dependences, signaling the influence of quantum critical fluctuations and disorder effects. Measurements of clean CePd2P2 furthermore show that applied pressure has an initial effect similar to alloying on the ferromagnetic order. From these results, CePd2P2 emerges as a keystone system to test theories such as the Belitz-Kirkpatrick-Vojta model for ferromagnetic quantum criticality, where distinct behaviors are expected in the dirty and clean limits.
13 citations
TL;DR: In this article, the X-ray absorption near-edge structures (XANES) of CeAl2 thin films of various thickness, 40-120 nm, at Al K, Ce L3-, and Ce M4,5-edges were reported.
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01 Jan 1988
172 citations
TL;DR: The lifetime broadening of some rare-earth-edge x-ray absorption spectra (XAS) is partially removed by deconvolving high quality data and the ligand field splitting of dipolar resonances is clearly resolved.
Abstract: The lifetime broadening of some rare-earth ${L}_{\mathrm{III}}$-edge x-ray absorption spectra (XAS) is partially removed by deconvolving high quality data. The ligand field splitting of dipolar resonances is clearly resolved. Exposed pre-edge structure is compared to atomic multiplet calculations of the $2p\ensuremath{\rightarrow}4f$ quadrupolar excitations. Ratios are thereby determined for the quadrupolar/dipolar oscillator strengths. Deconvolved XAS data of Ho${(\mathrm{N}{\mathrm{O}}_{3})}_{3}$ are compared to inelastic x-ray scattering measurements showing experimentally that the latter cannot reproduce a narrowed XAS.
50 citations
TL;DR: In this article, the X-ray absorption near edge structure (XANES) spectra of a series of ceria samples doped with trivalent rare earth oxide have been measured at the L-III edges of the dopants and the cerium.
42 citations
TL;DR: The results all indicate that Cr substitution drives this system from a mixed-valent Ce state at x=1.0 to a Kondo or heavy-fermion state with increasing x.
Abstract: Structural, thermal, magnetic, transport, and Ce ${L}_{3}$-edge spectroscopic measurements on the Ce(${\mathrm{Mn}}_{\mathrm{x}}$${\mathrm{Cr}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${)}_{2}$${\mathrm{Si}}_{2}$ series are presented. These results all indicate that Cr substitution drives this system from a mixed-valent Ce state at x=1.0 to a Kondo or heavy-fermion state with increasing x. The reflection of the Ce valence-state variation (from ${L}_{3}$ measurements) in the electronic specific heat coefficient and lattice parameters is discussed. The magnetic and transport measurements indicate that the Ce spin-flip scattering processes (i.e., the Kondo effect) apparently thrive within the Mn-moment antiferromagnetically ordered phase of these compounds.
23 citations
TL;DR: In this article, an X-ray absorption spectroscopy (XAS) investigation performed at the L edges of the rare earth and at the K edge of iron in the R-Fe intermetallic compounds (La,Ce)2Fe14BHx and Ce2Fe17(H,N)x, elucidate the role of the interstitial doping on the electronic and magnetic properties of these systems.
Abstract: We present an X-ray absorption spectroscopy (XAS) investigation performed at the L edges of the rare earth and at the K edge of iron in the R-Fe intermetallic compounds (La,Ce)2Fe14BHx and Ce2Fe17(H,N)x, to elucidate the role of the interstitial doping on the electronic and magnetic properties of these systems. Comparison with X-ray circular magnetic dichroism (XCMD) experiments has been carried out to clarify the localization of 4f magnetic moment at the Ce sites upon hydriding. Both XAS and XCMD results evidence the interplay between the structural and magnetic changes that are associated with the modification of the hybridization between the Fe(3d) and Ce(5d) bands.
20 citations