X-ray powder diffraction and high-resolution electron microscopy studies of new intergrowth compounds between Ba(Nb,Zr)O3 and NbO
2001 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, Vol. 314, no 1-2, 67-77 p.Article in journal (Refereed) Published
The structure of Ba2Nb5O9 can be described as intergrown layers of perovskite (BaNbO3) and NbO. The compound is a member of the BanNbn+3mO3(n+m) homologous series where n and m are the perovskite and NbO slab widths, respectively. The substitution of Zr for Nb according to the formula Ba2Nb5−xZrxO9 has been investigated. The increase of the c axis length as a function of the overall composition shows, in combination with microanalysis in scanning and transmission electron microscopes, that the maximum value of x is approximately 0.6. The microanalysis indicates that Zr prefers the MO6 octahedra in the perovskite slab. The X-ray powder diffraction (XRD) analysis and high-resolution electron microscopy (HREM) images show that for 0.6≤x≤1.5 a disordered intergrowth of Ba(Nb;Zr)O3 and NbO layers is formed. The XRD patterns and microanalyses of cation content showed that a new homologue Ba3(Nb,Zr)6O12 with n:m=3:1 in the series Ban(Nb;Zr)n+3mO3(n+m) is formed in some of these samples. It has the unit cell parameters a=4.1725(6) Å and c=16.429(3) Å and crystallises in space group P4/mmm, Z=1. The structure of this compound was determined by comparing simulated and experimental HREM images.
Place, publisher, year, edition, pages
2001. Vol. 314, no 1-2, 67-77 p.
scanning and transmission, electron microscopy
Research subject Inorganic Chemistry
IdentifiersURN: urn:nbn:se:su:diva-43877DOI: 10.1016/S0925-8388(00)01224-XOAI: oai:DiVA.org:su-43877DiVA: diva2:371579