X-ray structure and microstructure determination of the mixed sesquioxides (Eu_1−xYb_x)₂O₃prepared by a sol–gel process

Abstract

Polycrystalline samples of (Eu1−xYbx)2O3 (x = 0.0, 0.1, 0.2, 0.5, 0.8, 0.9 and 1.0) were synthesized by a sol–gel process. X‐ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range of x. The lattice parameters are found to vary linearly with the composition x. The cationic distribution over the two non‐equivalent sites 8b and 24d of the space group is found to be random in the range 0.0 < x≤ 0.5 and preferential in the range 0.5 < x≤ 1.0. Replacing Eu3+ and Yb3+ by each other introduces slight changes in the atomic coordinates. Crystallite size and microstrain analysis are performed on single and multiple orders for each sample using profile fitting and the Warren–Averbach method. The obtained values of microstrain are correlated with the distribution of the rare earth (RE) ions over the two cationic sites of the structure. The average crystallite size ranges from 35 to 96 nm and the mean‐square strain from 0.052 to 0.225 × 10−2.

X‐ray diffraction analysis of powder and thin film of (Gd1‐xYx)2O3 prepared by sol‐gel process

“…In a previous work [19,22], we found a similar random distribution of cations in (Er 1-q Gd q ) 2 O 3 and (Gd 1-q Ho q ) 2 O 3 which is attributed to the small difference in cationic radii. Depending on the difference in cationic radii, a random distribution is obtained whenever the difference between the cationic radii is small (e.g Y 2-q Re q O 3 , Re = Dy and Ho, [15,25], and preferential one is obtained for longer difference in radii (e.g Eu 2-q Yb q O 3 [20]; Y 2-q Gd q O 3 [26] and Y 2-q Eu q O 3 [17] ). Nevertheless, a random cationic distribution was found in Sm 2-q Y q O 3 [27] where partitioning was expected because of the relatively big difference in cationic radii.…”

“…Applying x-ray diffraction and magnetic susceptibility measurements, the cation ordering has been studied for a number of diluted magnetic semiconductors Y 2-x Ho x O 3 [15], Tm x Y 2-x O 3 [16], (YEu) 2 O 3 [17] and Y 2-x Gd x O 3 [18]. In a previous work we studied the mixed rare earth oxides ( [20,21] and (Gd 1-x Ho x ) 2 O 3 and (Gd 1-x Yb x ) 2 O 3 [22]. We have found random distribution of Er 3+ and Gd 3+ among the two different cationic sites, but preferentially for Eu 3+ and Yb…”

Fascinating functional properties of Mn:Gd2O3 nanocrystalline phosphor

“…The cation distribution has been studied for a number of mixed oxides applying X-ray diffraction and magnetic susceptibility measurements; Y 2-x Sm x O 3 [12], Tm x Y 2-x O 3 [13] and Y 2-x Gd x O 3 [14]. In previous works, we studied the mixed rare earth oxides (Er 1-x Gd x ) 2 O 3 [15], (Eu 1-x Yb x ) 2 O 3 [15,16] and (Gd 1-x Ho x ) 2 O 3 , (Gd 1-x Yb x ) 2 O 3 [17]. Anomalous concentration dependence is found in magnetic susceptibility of (Dy 1-x Er x ) 2 O 3 which is correlated to the cationic preferential distribution over the two crystallographic sites 8b and 24d [18].…”

Characterization of phases in the V2O5–Yb2O3 system obtained by high-energy ball milling and high-temperature treatment

“…4a) shows a broad absorption band in the wavenumber range from 645 to 300 cm -1 , of distinct extremes at 565, 395 and 335 cm -1 and an inflection point at * 500 cm -1 . These bands can be assigned to the stretching vibrations of Yb-O in the deformed YbO 6 octahedrons [23][24][25][26] and the stretching vibrations of the deformation bridge bonds Yb-O-Yb or O-Yb-O [23][24][25][26]. In the IR spectra of the solid solution (Fig.…”