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

Journal Article · Wed Sep 15 04:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.06.002· OSTI ID:21432468

Brant, William R ^[1]; Schmid, Siegbert ^[1]; Qinfen, Gu ^[2]; Withers, Ray L ^[3]; Hester, James; Avdeev, Maxim ^[4]

---

1. School of Chemistry, University of Sydney, Sydney, NSW 2006 (Australia)
2. Australian Synchrotron, 800 Blackburn Rd, Clayton, VIC 3168 (Australia)
3. Research School of Chemistry, Australian National University, Canberra, ACT 0200 (Australia)
4. Bragg Institute, Australian Nuclear Science and Technology Organisation, Menai, NSW 2234 (Australia)

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.

• OSTI ID: 21432468
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 9 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALINE EARTH METAL COMPOUNDS
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DIFFRACTION
DIFFUSE SCATTERING
DISPERSIONS
ELECTRON DIFFRACTION
EXPANSION
HOMOGENEOUS MIXTURES
LATTICE PARAMETERS
MINERALS
MIXTURES
NEUTRON DIFFRACTION
NIOBIUM COMPOUNDS
OXIDE MINERALS
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHASE TRANSFORMATIONS
REFRACTORY METAL COMPOUNDS
SCATTERING
SOLID SOLUTIONS
SOLUTIONS
STRONTIUM COMPOUNDS
STRONTIUM TITANATES
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
TETRAGONAL LATTICES
THERMAL EXPANSION
TITANATES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION