Vibrational Spectroscopy of the C-Form of Yttrium Sesquioxide

Repelin, Y.; Proust, C.; Husson, E.; Bény, Jean-Michel

doi:10.1006/jssc.1995.1326

Cited by 188 publications

(137 citation statements)

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“…3). This assignment is in agreement with those previously done, based on Y 2 O 3 single crystal measurements, 11,15,27 except for the A g peak at 495 cm À1 in Sc 2 O 3 (431 cm À1 in Y 2 O 3 ). The symmetry of the peak at 359 cm À1 is given as E g þ F g not because of an ambiguity but rather due to the presence of two peaks with different symmetry and coinciding frequencies.…”

Section: A General Dependenciessupporting

confidence: 93%

“…Although there are 22 Ramanactive modes, 4A g þ 4E g þ 14F g , the number of the experimentally observed peaks in the Raman spectra is smaller. 11,12,15 The Raman spectra of the studied samples with single (or dominating) C-type phase are displayed in Fig. 2 where, due to the good signal-to-noise ratio, even the weak peaks can be unambiguously detected.…”

Section: A General Dependenciesmentioning

confidence: 99%

“…The crystal structure of this phase belongs to the bixbyite-type [of the mineral (Mn,Fe) 2 O 3 ]. It can be regarded as an oxygen-deficient superstructure of the simpler CeO 2 (with CaF 2 -type crystal structure) if each fourth oxygen atom from the oxygen chains, parallel to all h100i crystal directions, is removed 11,12 (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

“…The most informative papers we found, in order of the increasing ionic radius of the rare earth, are for Sc-Refs. 12 11,12,15,22,26,27,31 only in few of them 11,12,27 polarized Raman spectra are shown. In some works, the symmetry of the phonon modes, giving rise to the observed peaks in the Raman spectra of Sc 2 3 11,15,27 this assignment is supported by the published experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study

Abrashev

Todorov

Geshev

2014

Journal of Applied Physics

129

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Dielectric and optical properties of epitaxial rare-earth scandate films and their crystallization behavior Appl. Phys. Lett. 88, 262906 (2006) Raman spectra of R 2 O 3 (R-Sc, Er, Y, Ho, Gd, Eu, and Sm) powders with C-type bixbyite crystal structure are measured. With the help of these data and ones, previously published for other oxides from the same structural family, general dependencies of the frequencies of the Raman peaks on the cubic crystal unit cell parameter are constructed. Using these dependencies and knowing the symmetry of the peaks for one of the oxides, determined from previous single-crystal measurements, it is possible to find out the symmetry of the peaks from the spectra of all compounds. It was found that the frequency of the six lowest frequency peaks scales with the square root of the mass of the rare earth showing that mainly R ions take part in these vibrations. These results agree with performed here lattice dynamical calculations. The anomalous softening of the frequency of some peaks in the spectra of Eu 2 O 3 is discussed. V C 2014 AIP Publishing LLC.

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Section: A General Dependenciessupporting

confidence: 93%

Section: A General Dependenciesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study

Abrashev

Todorov

Geshev

2014

Journal of Applied Physics

129

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“…Together with Raman bands characteristic for cubic phase of Y 2 O 3 , in spectra of all powders luminescence lines in region from 515 to 570 nm were observed after excitation with 514.5 nm. Since no luminescence is observed by RS from pure Y 2 O 3 in the same spectral region [24], the occurrence of luminescence lines in the studied powders was related to the presence of very small amount of REE ions substituted in the cation sites of Y 2 O 3 crystal lattice. The effect of mechanical treatment on the luminescence is significant.…”

Section: Resultsmentioning

confidence: 89%

Influence of mechanochemical processing to luminescence properties in Y2O3 powder

Gajović

Tomašić

Djerdj

et al. 2008

Journal of Alloys and Compounds

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In high purity Y 2 O 3 powders presence of small amount of erbium ions in cation sites was identified due to the luminescence bands observed by Raman spectrometer. The decrease of the luminescence intensity during high-energy ball-milling was explained. The mechanochemical processing induced the changes of Y 2 O 3 microstructure introducing distortion of the crystal lattice and oxygen vacancies in the cubic phase, substitution of tungsten at the cation sites in c-Y 2 O 3 , and incomplete phase transition of Y 2 O 3 from the cubic to the monoclinic structure. The influence of the particle-size decrease, caused by ball-milling, to luminescence was also considered.Keywords: Oxide materials; Mechanochemical processing; Microstructure; Luminescence IntroductionYttrium sesquioxide (Y 2 O 3 ) ceramics have been intensively investigated for different technological purposes. For decades yttrium oxide has been an important material in ceramic industry, from constituent of ceramic superconductors [1,2], to wellknown YSZ ceramics [3,4]. Y 2 O 3 is also used in electronic applications as a part of metal-oxide-semiconductor heterostructures in MOS transistors [5][6][7][8]. It also plays an important role in preparation of novel light-emitting materials. Y 2 O3 is used as a refractory matrix in rare earth ion doped laser materials [9]. It is selected as a host because of favorable thermomechanical properties (high melting point, phase stability, low thermal expansion). A very good substitution of dopants is insured by similar crystal-chemical constraints for rare earth ions and yttrium [9,10]. Y 2 O 3 structure corresponds to the C-type cubic bixbyite structure, space group Ia3 [11,12] with 16 formula units in the elementary cell. There are 32 cation (six-fold coordinated) sites available for substitution of lanthanide ions: eight are centrosymmetric with C3i symmetry and 24 noncentrosymmetric with C 2 symmetry (Fig. 1a). The sites with C 3i symmetry have a smaller crystal field, so Stark splitting of 4f orbital is smaller [13]. Moreover, since C 3i site has an inversion center, the selection rules forbid the electron-dipole (ED) transitions, but thermal fluctuations of Y 2 O 3 lattice destroy the perfect C 3i symmetry locally [14], and the ED transitions can occur. There is no center of inversion in the C 2 site and the luminescence of incorporated lanthanide ions is predominantly connected with this site. At the pressure of 10-13 GPa cubic Y 2 O 3 exhibits the first-order reconstructive (irreversible) phase transition [15] to monoclinic structure, space group C2/m [16]. Monoclinic structure has 6 Y 2 O 3 formula units in the elementary cell with 3 nonequivalent cation sites (seven-fold coordinated) and Cs symmetry (Fig. 1b). Bihari et. al [17] observed three sets of luminescence lines in doped monoclinic Y 2 O 3 , which correspond to three nonequivalent cation sites. In this work the luminescence bands was observed in high purity Y 2 O 3 (99.99%). The origin of the luminescence bands was identified and their propert...

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Characterization of ytterbium-yttrium mixed oxides using Raman spectroscopy and x-ray powder diffraction

Panitz

1999

J. Raman Spectrosc.

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Ytterbium-yttrium mixed oxides, which are potential emitter materials for thermophotovoltaic energy converters, were prepared using two different synthesis methods. The results of a characterization using Raman spectroscopy and x-ray powder diffraction (XRD) are presented. The purpose of this study was to confirm whether the materials prepared are indeed substitutional solid solutions of ytterbium oxide and yttrium oxide. Both XRD and Raman spectroscopy are established techniques for the analysis of solid solutions. Linear relationships between the Raman band position and the composition of mixed crystals are known for solid solutions with one active Raman mode. An aspect of this study was the investigation of the relationship between composition and band position and linewidth of vibrational modes when applying Raman techniques to a system with several vibrational modes. A linear relationship between the band position of a vibrational mode at about 600 cm −1 , which is assigned to a stretching vibration, and the ytterbium content of the material was observed. Using an empirical fit to the most intense band around 370 cm −1 , even a substitution of 2 mol% Yb may be detected using non-linear least-squares data analysis. In addition, a discussion of additional features observed in the Raman spectra at Raman shifts >650 cm −1 is presented.

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Vibrational Spectroscopy of the C-Form of Yttrium Sesquioxide

Cited by 188 publications

References 0 publications

Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study

Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study

Influence of mechanochemical processing to luminescence properties in Y2O3 powder

Characterization of ytterbium-yttrium mixed oxides using Raman spectroscopy and x-ray powder diffraction

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