Crystal structures and reference powder patterns of BaR2ZnO5 (R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, and Tm)

Abstract

Reference x-ray powder patterns and the crystal structures of the lanthanide compounds, BaR2ZnO5, in which R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm, were determined by the x-ray Rietveld refinement technique. A structural trend was confirmed for this series of compounds. The compounds with smaller ionic radii (R = Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm) are isostructural to the orthorhombic “green phase” (BaY2CuO5). The lattice parameters for compounds with R = Tm to Sm range from a = 7.01855(9) Å to 7.20452(14) Å, b = 12.25445 (17) Å to 12.5882(2) Å, and c = 5.6786(14) Å to 5.81218(11) Å, respectively. R is sevenfold coordinated inside a monocapped trigonal prism. These prisms share edges to form wave-like chains parallel to the long b-axis. The BaR2ZnO5 compounds which contain larger size R (La and Nd) crystallize in the tetragonal space group I4/mcm. The lattice parameters are a = 6.90982(10) and c = 11.5977(2) Å for BaLa2ZnO5, and a = 6.75979(5) Å and c = 11.54560(12) Å for BaNd2ZnO5. The structure consists of ZnO4 tetrahedra (instead of planar CuO4 groups as found in BaR2CuO5) with 10-fold coordinated bicapped square prismatic Ba and 8-fold coordinated bicapped trigonal prismatic R ions between them. The reference x-ray powder patterns will be submitted to the Powder Diffraction File (PDF).

Citric based sol–gel synthesis and luminescence characteristics of CaLa2ZnO5:Eu3+phosphors for blue LED excited white LEDs

“…Based on both the theoretical simulation and XRD analysis by a software namely POWD, we found that the structures of them are tetragonal natured and the corresponding (h k l) values for the obtained diffraction peaks were indexed appropriately. Besides, CLZ crystal structure is similar to that of BaLa 2 ZnO 5 and BaNd 2 ZnO 5 , which are well agreement with the tetragonal structure [16,17]. Further heat treatment at 1000 • C, 1050 • C and 1100 • C leads to the enhancement in the diffraction peak intensity and reduction in FWHM due to the improvement of crystallinity and grain growth.…”

“…The ternary oxides XY 2 ZO 5 (X = Ba, Y = rare-earth, Z = Cu, Zn) are receiving much attention because of their very interesting structural, physical and chemical properties and additionally they exhibit special magnetic, optical and superconducting properties [15][16][17]. Owing to these reasons, in the present investigation we have chosen CaLa 2 ZnO 5 as the host matrix for doping Eu 3+ ions.…”

Near white light emission of BaY2ZnO5 doped with Dy3+ ions

“…89-5856) without any impurities, indicating that the Dy 3+ ions substituted the Y 3+ ions. Using the Rietveld refinement method, Kaduk et al [14] found that BaY 2 ZnO 5 and BaDy 2 ZnO 5 are isostructures with a space group of Pbnm. The full width at half maximum (FWHM) of the peaks did not show any obvious differences with an increase in Dy 3+ concentration when trivalent terbium ions (0.97Å) [15] were introduced to substitute the trivalent yttrium ions (0.96Å) [15] in the Ba(Y,Dy) 2 ZnO 5 system.…”

“…where x c is the critical concentration, N is the number of Y 3+ ions in the BaY 2 ZnO 5 unit cell (N = 8 in BaY 2 ZnO 5 ), and V is the volume of the unit cell (V = 497.964 × 10 −30 m 3 in this case) [14]. For the 4 F 9/2 → 6 H 13/2 transition, the critical concentration is estimated to be about x c = 0.07, at which point the measured emission intensity and decay time begin to decrease rapidly.…”

Investigation of crystallographic sites of Eu3+ in La2BaZnO5 by site-selective laser-excitation spectroscopy

“…Ternary oxides of Ln 2 BaZnO 5 (Ln is trivalent lanthanide ions) crystallize in two different structural phases depending on the Ln elements involved [1]. The Ln 2 BaZnO 5 compounds with the ions Sm, Eu, Gd, Dy, Ho, Y, Er or Tm crystallize in an orthorhombic phase with the space group Pnma and the compounds with La or Nd ions crystallize in a tetragonal phase with space group I4/ mcm.…”