XRD, IR, and Raman investigations of structural properties of Dy_2‐xHo_x O₃ prepared by sol gel procedure

Abstract

The Rare earth mixed oxides Dy 2-x Ho x O 3 (0.0 ≤ x ≤ 2.0) solid solution was synthesized by a sol-gel process. X-ray diffraction (XRD) data were collected and crystal structure and microstructure analyses were performed applying Rietveld refinement method. Infrared and Raman spectroscopy were used to define the microstructure and to locally probe the structure of the samples. The cationic distribution over the two nonequivalent sites 8b and 24d of the space group Ia3 is found to be randomly. The crystallite size and microstrain as well as Raman modes positions are influenced by Ho 3+ concentration. The apparent size is isotropic but significant anisotropy is found for the microstrain with its largest value along the crystallographic direction [h00]. Inspite the single phase solid solution confirmed by Rietveld analysis for all samples, Raman spectra detected the coexistence of two phases; cubic and distorted monoclinic of too small amount or highly disordered, i.e. amorphous like, to be detected by XRD. The result indicates the ability of Raman spectroscopy to detect minor phases in solid solutions.

Raman and Fluorescence Spectroscopy of CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7

“…However, none of the reported spectra in literature has shown all the predicted bands. Heiba attributed this to the accidental degeneracies or low Raman scattering cross sections of the corresponding vibrations [17]. In the present study, the Raman spectra with excitation of 442 nm and 633 mm were identical.…”

“…where 22 Raman bands (Ag, Eg, and Fg) are predicted in the lower wavenumber area [6,17]. However, none of the reported spectra in literature has shown all the predicted bands.…”

Raman scattering of rare earth sesquioxide Ho2O3: A pressure and temperature dependent study

“…The 48 oxygen ions in the body-centered cell are on general positions 48e with C 1 site symmetry. 3 The electronic configuration of the Ho ion in Ho 2 O 3 is [Xe] 4f 11 5s 2 5p 6 . The ten f-electrons are localized in the 4f shell with one f-electron in the conduction band making Ho trivalent.…”

“…The forty eight oxygen atoms in bcc structure are positioned at C 1 site symmetry. 3,8 The local axes of the C 3i sites are in the However, smaller numbers of modes are observed in practice in the Raman spectra; this may be due to the fact that some of the observed modes are actually superposition of closely spaced different type of modes, which are un-separated owing to a weak factor-group interaction.…”

Synthesis, structural and dielectric properties of Ho-doped SrBi2Nb2O9 prepared by Co-precipitation method

“…The spectra reveal a superimposition of three bands centered at 430, 615 and 805 cm −1 which are attributed to the characteristic vibration of SrBi2Nb2O9 [14]. A small, weak band appears at 473 cm −1 for the Ho-doped SBN which is attributed to the vibration of Ho-O bond [15]. Fig.…”