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Nanostructured crystals of fluorite phases Sr{sub 1-x}R{sub x}F{sub 2+x}(R are rare-earth elements) and their ordering. I. Crystal growth of Sr{sub 1-x}R{sub x}F{sub 2+x} (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu)

Journal Article · · Crystallography Reports
; ;  [1]
  1. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
Crystals of nonstoichiometric phases Sr{sub 1-x}R{sub x}F{sub 2+x} (R are 14 rare-earth elements) and the ordered phase Sr{sub 4}Lu{sub 3}F{sub 17} with a trigonally distorted fluorite lattice were grown by the Bridgman method. Ten of 26 Sr{sub 1-} {sub x}R{sub x}F{sub 2+x} crystals, where R = La-Ho or Y, melt congruently. The isoconcentration series Sr{sub 0.90}R{sub 0.10}F{sub 2.10} includes four crystals with R = Er-Lu. The compositions corresponding to the maxima for the latter crystals were not determined. The concentration series, in which the mole fraction of RF{sub 3} varies from 10 to 50 mol %, were obtained for the crystals with R = La, Nd, and Gd. Most of the crystals are of good optical quality. To evaluate the composition changes in the course of crystal growth, the cubic unit-cell parameters were determined by X-ray powder diffraction. The line-broadening analysis revealed a nonmonotonic change of microdistortions as regards both the rare-earth content and rare-earth series. The changes in the lattice parameters and the congruent-melting points of the Sr{sub 1-x}R{sub x}F{sub 2+x} phases in the rare-earth series reflect the morphotropic transitions in the series of pure RF{sub 3} despite the fact that SrF{sub 2} dominates in nonstoichiometric fluorite crystals.
OSTI ID:
22050865
Journal Information:
Crystallography Reports, Journal Name: Crystallography Reports Journal Issue: 1 Vol. 54; ISSN 1063-7745; ISSN CYSTE3
Country of Publication:
United States
Language:
English