Hard–soft chemistry of Sr1−xCaxCrO3–δ solid solutions12. (30th September 2016)

• Record Type: Journal Article
• Authors: Arevalo-Lopez, A. M.; Srinath, A.; Attfield, J. P.
• Is Part Of: Materials chemistry frontiers. Volume 1:Number 1(2017)
• Page Start: 172
• Page End: 175
• Publication Date: 2016-09-30
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/c6qm00136j
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : The lower temperature for superstructure formation is discovered to have a maximum near x = 0.5, evidencing an influence of Ca/Sr cation disorder in the Sr1− x Ca x CrO3− δ system. Abstract : Sr1− x Ca x CrO3− δ ( x = 0.25, 0.50, 0.75) solid solutions have been synthesised using the 'hard–soft' technique and structurally characterised. Sr1− x Ca x CrO3 phases were prepared under 'hard' high pressure and high temperature synthesis and then reduced at 'soft' low temperature conditions. Analysis by powder X-ray diffraction and Rietveld refinements reveals that the reduction of each composition gives two crystalline products, with 6H and 15R structure types previously reported in SrCrO3− δ . analogues. These results demonstrate that the 6H and 15R structures are stable for very high calcium contents up to x = 0.75 in Sr1− x Ca x CrO3− δ, although different structural motifs are observed for CaCrO3− δ . The Sr1− x Ca x CrO3− δ phase diagram shows that the lower temperature for superstructure formation has a maximum near x = 0.5, evidencing an influence of Ca/Sr cation disorder on oxygen vacancy order.