Details

Autor(en) / Beteiligte

• Brant, William R.
• Schmid, Siegbert
• Gu Qinfen
• Withers, Ray L.
• Hester, James
• Avdeev, Maxim

Titel

Temperature and composition dependent structural investigation of the defect perovskite series Sr{sub 1-x}Ti{sub 1-2x}Nb{sub 2x}O{sub 3}, 0{<=}x{<=}0.2

Ist Teil von

• Journal of solid state chemistry, 2010-09, Vol.183 (9)

Ort / Verlag

United States

Erscheinungsjahr

2010

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The crystal structure of the defect perovskite series Sr{sub 1-x}Ti{sub 1-2x}Nb{sub 2x}O{sub 3} has been investigated over a range of temperatures using high-resolution synchrotron X-ray diffraction, neutron diffraction and electron diffraction. Three distinct regions were observed: 0<x{<=}0.125 was a solid solution of Sr{sub 1-x}Ti{sub 1-2x}Nb{sub 2x}O{sub 3} with minor SrTiO{sub 3} intergrowth, 0.125<x{<=}0.2 was a pure Sr{sub 1-x}Ti{sub 1-2x}Nb{sub 2x}O{sub 3} solid solution adopting the cubic perovskite type structure (Pm3-bar m) and for x>0.2 Sr{sub 0.8}Ti{sub 0.6}Nb{sub 0.4}O{sub 3} and Sr{sub 3}TiNb{sub 4}O{sub 15} formed a two phase region. The cubic structure for Sr{sub 0.8}Ti{sub 0.6}Nb{sub 0.4}O{sub 3} was stable over the temperature range 90-1248 K and the thermal expansion co-efficient was determined to be 8.72(9)x10{sup -6} K{sup -1}. Electron diffraction studies revealed diffuse scattering due to local scale Ti/Nb displacements and slightly enhanced octahedral rotations that did not lead to long range order. The octahedral rotations were observed to 'lock-in' at temperatures below {approx}75 K resulting in a tetragonal structure (I4/mcm) with anti-phase octahedral tilting about the c-axis. - Graphical abstract: Change in cell dimensions for the series Sr{sub 1-x}Ti{sub 1-2x}Nb{sub 2x}O{sub 3}, 0{<=}x{<=}0.2.