Structure Study of Bi2.5Na0.5Ta2O9 and Bi2.5Nam−1.5NbmO3m+3 (m=2–4) by Neutron Powder Diffraction and Electron Microscopy

Topochemical Synthesis of a High‐Aspect‐Ratio Platelet NaNbO3 Template

“…The reason is that the cell parameters a and b increase with increasing m for the compounds Bi 2 O 2 [(Bi 0.5 Na m −1.5 )Nb m O 3 m +1 ]. A great strain occurs in the structure because of the major mismatch between the ideal [Bi 2 O 2 ] 2+ layer and the ideal perovskite, although it can be partly relieved by octahedral tilting in the perovskite layer 9 . This structural characteristic makes BNN5 formation more difficult.…”

“…SAED indicated that the diffraction pattern could be indexed to a tetragonal structure and the c ‐axis direction is perpendicular to the surface of the platelets. The SAED pattern also showed diffused scattering along the [00L] direction; it would be expected that either the [Bi 2 O 2 ] 2+ layer or the (A m –1 B m O 3 m +1 ) 2− pseudo‐perovskite slabs may vary slightly according to reference 9 . This was confirmed by the HTEM image; it could clearly be seen that the thickness of the [Bi 2 O 2 ] 2+ layers does not change, but the value of m in the perovskite slabs may vary between 2 and 5, which means that there is a co‐existence of a small amount of BNN2 and BNN4 in the sample.…”

Synthesis and formation mechanisms of high aspect ratio KNb5Bi2O16 template via topochemical method

“…And this strain could not be overcome thoroughly by the spinning of oxygen octahedral [13]. The more the amount of perovskie layer is, the greater this strain will be.…”

Hole conduction and electro-mechanical properties of Na0.5Bi2.5Ta2O9-based piezoelectric ceramics with the Li+/Ce3+/Sc3+ modification

“…Single phase was obtained for the NBTO-x (x ¼ 0-0.03), and all diffraction peaks of them can be indexed to the crystal structure of the reported NBTO (A2 1 am). 27 However, higher concentration Li þ /Ce 3þ /Sc 3þ substitution led to weak impurity phase observed at 2h ¼ 48.6 and 57.7 in the NBTO-0.04 and NBTO-0.05 patterns. Furthermore, Rietveld method was used to refine the lattice parameters of the samples, by using the GSAS-EXPGUI program.…”