Formation of a cubic Sr2MnWO6 phase at elevated temperature; a neutron powder diffraction study

✍ Scribed by A.K Azad; S.-G Eriksson

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 471 KB
• Volume: 126
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/s0038-1098(03)00280-1

✦ Synopsis

In a temperature dependent neutron powder diffraction (NPD) study we observed the high temperature cubic phase at 973 K in the polycrystalline double perovskite Sr 2 MnWO 6 . Rietveld analysis of the NPD data shows that the room temperature tetragonal phase exists up to 573 K (space group P4 2 =n; a ¼ 8.0119 (4) A ˚, c ¼ 8.0141(8) A ˚). At 773 K, the primitive tetragonal symmetry change to body-centred tetragonal (space group I4=m; a ¼ 5.6935(5) A ˚, c ¼ 8.077(1) A ˚) and finally at 973 K it becomes face-centred cubic (space group Fm-3m; a ¼ 8.0864(8) A ˚). The changes in the structural symmetry are connected to the small distortion of the B-site octahedra, which are insensitive to the Differential Thermal Analysis (DTA) signal.