Crystal structure and thermal expansion of PrGaO3 in the temperature range 12–1253 K

Structure of praseodymium and neodymium gallate glasses

“…An analysis of the neutron diffraction data assuming a glass composition of R 3 Ga 5 O 12 did not change the first peak position in ΔG R (r) or ΔG(r) and led to coordination numbers of n O Ga = 4.2(1) and n O R = 7.7(2). In crystalline rare-earth gallates the nearest-neighbor R-Ga and R-R distances are in the range of 3.13-3.32 Å and 3.55-3.83 Å, respectively [23][24][25][26]28,29,[45][46][47]. By comparison, the second peak in ΔG R (r) occurs at 3.76(2) Å and has a shoulder on its small r side in the region 3.38-3.44 Å.…”

“…2. By comparison with the crystal structures of RGaO 3 (R =Pr or Nd) [23][24][25][26], R 4 Ga 2 O 9 [28,29] (R =Pr or Nd), Nd 3 GaO 6 [45,46] and Nd 3 Ga 5 O 12 [47], the first peak in Pr G(r) at 1.85(2) Å or in Nd G(r) at 1.86(2) Å is attributed to Ga-O correlations and its integration over the range 1.66 ≤ r(Å) ≤ 2.09 gives a coordination number n O Ga = 4.2(1). The second peak in Pr G(r) at 2.44(2) Å or in Nd G(r) at 2.42(2) Å will have a strong contribution from R-O correlations and, in keeping with the larger coherent neutron scattering length of Nd, this peak is more intense for the neodymium gallate glass.…”

“…This distance is comparable to the position of the second peak in ΔG(r) at 3.03(2) Å. In crystalline rare-earth gallates the nearestneighbor Ga-Ga distances are 3.50 Å for Nd 3 Ga 5 O 12 [47], 3.47-3.56 Å for R 4 Ga 2 O 9 (R =Pr or Nd) [28,29], 3.84-3.86 Å for RGaO 3 (R =Pr or Nd) [23][24][25][26], and 5.23 Å for Nd 3 GaO 6 [45,46].…”

“…0.6975) [20]. They also share a similar structural chemistry [21,22], e.g., the rare-earth gallates PrGaO 3 and NdGaO 3 have a perovskite structure [23][24][25][26][27] while Pr 4 Ga 2 O 9 and Nd 4 Ga 2 O 9 also share a common crystal structure [28,29]. By treating Pr 3 + and Nd 3 + as isomorphic pairs and by measuring the diffraction patterns of the glasses it is possible to probe separately the coordination environments of both the rare-earth and gallium atoms.…”

Spin-state transitions in PrCoO3studied with neutron powder diffraction

“…However, the average Co-O bond length, which is )iso, respectively; the <Co-O> is from refinements with the Uaniso; the data of LaCoO3 and PrGaO3 are from references. 30 The windows of the vertical scale in this plot are set for <Co-O> , <Cr-O> and <Ga-O> to have an identical range of ∆<M-O>/<M-O>. (b) temperature dependences of thermal conductivity κ and magnetic susceptibility χ.…”