scholarly journals X-Ray Absorption Spectroscopy of the Rare Earth Orthophosphates

1993 ◽  
Vol 307 ◽  
Author(s):  
D. K. Shuh ◽  
L. J. Terminello ◽  
L. A. Boatner ◽  
M. M. Abraham
Keyword(s):  
Rare Earth ◽  
Absorption Spectroscopy ◽  
Total Yield ◽  
Electronic Transitions ◽  
X Ray ◽  
Trivalent State ◽  
Theoretical Investigations ◽  
Radiation Laboratory ◽  
X Ray Absorption ◽  
The Rare Earth

ABSTRACTX-ray Absorption Spectroscopy (XAS) of the Rare Earth (RE) 3d levels yields sharp peaks near the edges as a result of strong, quasi-atomic 3d104fn→3d94fn+1 transitions and these transitions exhibit a wealth of spectroscopic features. The XAS measurements of single crystal REPO4 (RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Er) at the 3d edge were performed in the total yield mode at beam line 8–2 at the Stanford Synchrotron Radiation Laboratory (SSRL). The XAS spectra of the RE ions in the orthophosphate matrix generally resemble the XAS of the corresponding RE metal. This is not unexpected and emphasizes the major contribution of the trivalent state to the electronic transitions at the RE 3d edges. These spectra unequivocally identify the transitions originating from well-characterized RE cores and correlate well with previous theoretical investigations.

Characterization of Ce-Doped LaPO4 by X-Ray Absorption Spectroscopy

1993 ◽  
Vol 329 ◽  
Author(s):  
D. K. Shuh ◽  
L. J. Terminello ◽  
L. A. Boatner ◽  
M. M. Abraham ◽  
D. Perry
Keyword(s):  
Absorption Spectroscopy ◽  
Full Width Half Maximum ◽  
Energy Shift ◽  
Total Electron Yield ◽  
Total Electron ◽  
X Ray ◽  
Trivalent State ◽  
Radiation Laboratory ◽  
X Ray Absorption

AbstractX-ray Absorption Spectroscopy (XAS) of the Rare Earth (RE) 3d levels yields sharp peaks near the edges as a result of strong, quasi-atomic 3d104fn→3d94fn+1 (M4,5) transitions that contain a wealth of spectroscopic features. XAS is a useful technique for the characterization of 4f-occupancy, 4f-hybridization, and valence in RE-containing materials. The XAS measurements of the single crystal RE-orthophosphates, as well as a range of Ce- doped (˜l–30%) LaPO4 hosts were performed at the 3d edge in the total electron yield mode at beamline 8–2 at the Stanford Synchrotron Radiation Laboratory (SSRL). The XAS spectra of the RE ions in the orthophosphate matrix generally resemble that of the corresponding RE metal and emphasize the major contribution of the trivalent state to the electronic transitions occurring at the 3d edge. There is no energy shift of the La and Ce absorption peaks with Ce doping and furthermore, no additional transitions are observed in either spectral region. However, accompanying the Ce doping there is a significant narrowing of the La absorption peak full width half maximum that contrasts to the Ce features that exhibit no contraction. The La and Ce spectra indicate that the Ce-doping of LaPO4 is purely substitutional.

scholarly journals Determination of the relative concentrations of rare earth ions by x-ray absorption spectroscopy: Application to terbium mixed oxides

1986 ◽  
Vol 47 (4) ◽  
pp. 413-416 ◽  
Author(s):  
G. van der Laan ◽  
J.C. fuggle ◽  
M.P. van Dijk ◽  
A.J. Burggraaf ◽  
J.-M. Esteva ◽  
...  
Keyword(s):  
Rare Earth ◽  
Absorption Spectroscopy ◽  
Mixed Oxides ◽  
Rare Earth Ions ◽  
X Ray ◽  
X Ray Absorption

Structural Characterisations of Rare Earth-Rich Glasses for Nuclear Waste Immobilisation

2003 ◽  
Vol 807 ◽  
Author(s):  
I. Bardez ◽  
D. Caurant ◽  
F. Ribot ◽  
P. Loiseau ◽  
J. L. Dussossoy ◽  
...  
Keyword(s):  
Rare Earth ◽  
Nuclear Waste ◽  
Glass Composition ◽  
Optical Absorption Spectroscopy ◽  
X Ray ◽  
Liquid Wastes ◽  
X Ray Absorption ◽  
Glassy Matrices ◽  
Characterisation Methods ◽  
The Rare Earth

ABSTRACTNew glassy matrices, able to incorporate new highly concentrated radioactive liquid wastes (HLW), are being studied. Investigations were performed on rare earth-rich glasses, known as very durable matrices. The selected basic glass composition was (wt. %): 51.0 SiO2 – 8.5 B2O3–12.2 Na2O – 4.3 Al2O3 – 4.8 CaO – 3.2 ZrO2 – 16.0 Nd2O3. To determine both the environment around the rare earth in this glass and its evolution according to its concentration (1.3 – 30 wt. % Nd2O3), EXAFS (Extended X-Ray Absorption Fine Structure) spectroscopy at the LIII-edge of neodymium and optical absorption spectroscopy were used. By coupling these two characterisation methods, several hypotheses are proposed about the nature of the rare earth neighbouring in the glass.

scholarly journals Electronic Structure of the Rare-Earth Nitrides

2021 ◽  
Author(s):  
◽  
A. R. H. Preston
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
X Ray ◽  
Rare Earth Nitrides ◽  
Wide Range ◽  
X Ray Absorption ◽  
The Rare Earth

<p>The rare-earth nitrides (ReNs) are a class of novel materials with potential for use in spintronics applications. Theoretical studies indicate that among the ReNs there could be half-metals, semimetals and semiconductors, all exhibiting strong magnetic ordering. This is because of the complex interaction between the partially filled rare-earth 4f orbital and the nitrogen 2p valence and rare-earth 5d conduction bands. This thesis uses experimental and theoretical techniques to probe the ReN electronic structure. Thin films of SmN, EuN, GdN, DyN, LuN and HfN have been produced for study. Basic characterization shows that the films are of a high quality. The result of electrical transport, magnetometry, and optical and x-ray spectroscopy are interpreted to provide information on the electronic structure. SmN, GdN, DyN are found to be semiconductors in their ferromagnetic ground state while HfN is a metal. Results are compared with density functional theory (DFT) based calculations. The free parameters resulting from use of the local spin density approximation with Hubbard-U corrections as the exchange-correlation functional are adjusted to reach good agreement with x-ray absorption and emission spectroscopy at the nitrogen K-edge. Resonant x-ray emission is used to experimentally measure valence band dispersion of GdN. No evidence of the rare-earth 4f levels is found in any of the K-edge spectroscopy, which is consistent with the result of M-edge x-ray absorption which show that the 4f wave function of the rare-earths in the ReNs are very similar to those of rare-earth metal. An auxillary resonant x-ray emission study of ZnO is used to map the dispersion of the electronic band structure across a wide range of the Brillouin zone. The data, and calculations based on GW corrections to DFT, together provide a detailed picture of the bulk electronic band structure.</p>

X-ray absorption spectroscopy of rare earth intermediate oxides

1987 ◽  
Vol 127 ◽  
pp. 367-372 ◽  
Author(s):  
M. Gasgnier ◽  
L. Eyring ◽  
R.C. Karnatak ◽  
H. Dexpert ◽  
J.M. Esteva ◽  
...  
Keyword(s):  
Rare Earth ◽  
Absorption Spectroscopy ◽  
X Ray ◽  
X Ray Absorption
Sign in / Sign up

Export Citation Format

Share Document