Low thermal expansion materials : a comparison of the structural behaviour of La{sub 0.33}Ti{sub 2}(PO{sub 4}){sub 3}, Sr{sub 0.5}Ti{sub 2}(PO{sub 4}){sub 3} and NaTi{sub 2}(PO{sub 4}){sub 3}.

Journal Article · Thu Dec 31 23:00:00 EST 1998 · Int. J. Inorg. Mater.

DOI:https://doi.org/10.1016/S1463-0176(99)00008-3· OSTI ID:942636

Lightfoot, P; Woodcock, D A; Jorgensen, J; Short, S

Variable temperature neutron powder diffraction data have been used to examine the structural mechanism of unusual thermal expansion behaviour in La{sub 0.33}Ti{sub 2}(PO{sub 4}){sub 3} (LaTP). These data are compared to those we have recently reported for the related systems NaTi{sub 2}(PO{sub 4}){sub 3} (NaTP) and Sr{sub 0.5}Ti{sub 2}(PO{sub 4}){sub 3} (SrTP), which differ in the extent of occupation of the extra-framework Mi(La, Sr, Na) cation sites. The root cause of the unusual behaviour is ascribed to the different expansivities of the occupied and vacant MI sites. This leads to cooperative rotations of TiO{sub 6} and PO{sub 4} polyhedra, which can be used to quantify and rationalize the overall anisotropic thermal expansion behaviour.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 942636
• Report Number(s): ANL/MSD/JA-33276
• Journal Information: Int. J. Inorg. Mater., Journal Name: Int. J. Inorg. Mater. Journal Issue: 1999 Vol. 1
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
CATIONS
CRYSTAL STRUCTURE
DATA
DIFFRACTION
LANTHANUM OXIDES
MATERIALS
NEUTRON DIFFRACTION
NEUTRONS
PHOSPHORUS OXIDES
THERMAL EXPANSION
TITANIUM OXIDES