A universally applicable composite modulated structure approach to ordered Ba{sub x}M{sub y}Ti{sub 8-y}O{sub 16} hollandite-type solid solutions
- Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234 (Australia) and School of Chemistry, University of Sydney, Sydney, NSW 2006 (Australia)
- Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)
A wide range of barium titanate hollandites of the form Ba{sub x}{sup 2+}M{sub x}{sup 2+}Ti{sub 8-x}{sup 4+}O{sub 16} (M=Zn, Co, Mg, Fe and Mn) and Ba{sub x}{sup 2+}M{sub 2x}{sup 3+}Ti{sub 8-2x}{sup 4+}O{sub 16} (M=Fe) with nominal x ranging from 1.0 to 1.4 have been synthesized and examined to investigate the solid solution range and the nature of the ordering of the Ba ions. Electron diffraction studies confirm that the barium titanate hollandites are composite modulated single phase solid solutions made up of mutually incommensurable (along b) framework and Ba ion sub-structures. The overall superspace group symmetry was found to be I'2/m(0,x2,0)1. The symbol I' here refers to the superspace centering operation {l_brace}x{sub 1}+12,x{sub 2}+12,x{sub 3}+12,x{sub 4}+12{r_brace} (see below). Both the framework and the Ba sub-structures have the same I2/m average structure space group symmetry. The solid solution ranges for the hollandites were calculated from the positions of well-defined superlattice peaks in X-ray diffraction patterns. The effect of cooling rate on Ba ion ordering is also examined.
- OSTI ID:
- 20725977
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 6 Vol. 178; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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