X-Ray and Neutron Powder Investigations of Pure and Yttrium Doped CeO₂ at Temperatures up to 1600 K

Positional disorder and diffusion path of oxide ions in the yttria-doped ceria Ce0.93Y0.07O1.96

“…Such an anisotropic feature in the neutron scattering amplitude distribution has been observed in the ceria materials. 6,7,20 The shift of oxide ions in the h111i directions has been reported in the bismuth oxide-based compounds 3,4,27,28 and b 0 phase in the Mg-Zr-O-N system. 29 These compounds have a defect fluorite-type structure, similar to the ceria-based materials.…”

“…These features are consistent with the previous results in Rietveld analyses for the nondoped and doped ceria materials. 6,7,[17][18][19][20][21] MEM analyses were carried out using the structure factors obtained in the Rietveld analysis. The number of structure factors derived in the analysis was 11.…”

“…The crystal structure of CeO 2Àd at high temperatures has been investigated by some researchers. [17][18][19][20][21] Berber et al 20 studied the scattering amplitude distribution in Ce 1Àx Y x O 2Àx/2 samples at high temperatures (x = 0-0.18). However, these previous works on the disorder of oxide ions were insufficient.…”

Atomic Displacement Parameters of Ceria Doped with Rare-Earth Oxide Ce0.8R0.2O1.9 (R = La, Nd, Sm, Gd, Y, and Yb) and Correlation with Oxide-Ion Conductivity

“…All the atomic displacement parameters, U C (R), U C (CeO 2 ), U O (R), and U O (CeO 2 ), increase with an increase of temperature, which is consistent with the previous works. [20][21][22]25,26 The increase of atomic displacement parameters with temperature indicates the increase of thermal vibrations and dynamic positional disorders of cations and anions. As shown in Figure 5, at a certain temperature, the thermal parameters of cation U C (R) in Ce 0.8 R 0.2 O 1.9 are larger than U C (CeO 2 ), which indicates that the positional disorder of cations in Ce 0.8 R 0.2 O 1.9 is also larger compared with that in CeO 2 .…”

“…The unit-cell parameter of Ce 1-x R x O 2-x/2 has been extensively investigated by numerous researchers. 2,3,7,8,[17][18][19][20][21][22][23][24][25][26] The unit-cell parameter of Ce 0.8 R 0.2 O 1.9 increases with ionic radius of dopant cation. 7,17,18 The atomic displacement parameters of cations U C and of oxide ions U O and positional disorders of CeO 2 , CeO 2-x , and Ce 1-x Y x O 2-x/2 have been reported by some researchers.…”