Diffuse X-ray scattering in the lead-free piezoelectric crystals Na1/2Bi1/2TiO3 and Ba-doped Na1/2Bi1/2TiO3

P. A. Thomas*, S. Trujillo, M. Boudard, S. Gorfman, J. Kreisel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

X-ray diffuse scattering has been measured by single-crystal X-ray diffraction on the lead-free piezoelectric perovskites Na0.5Bi0.5TiO3 (NBT) and (Na0.5Bi0.5)0.89Ba0.11TiO3 (NBT-Ba0.11). Evidence of a pronounced local structure or included phase different from the rhombohedral average symmetry (space group R3c), or of a modulated structure with a characteristic period of 40 Å, is presented for NBT from high-resolution synchrotron X-ray mapping and CCD diffractometer investigations. The additional scattering shows pronounced anisotropy and produces satellite peaks displaced by 0.2 in the h and k indices for reflections such as {640} indexed on the pseudo-cubic unit cell with a = 7.761(2) Å. By contrast, weaker, less anisotropic diffuse scattering is observed for tetragonal NBT-Ba0.11 (space group P4mm), which is directed along the pseudo-cubic 〈110〉. The lack of satellite peaks and pronounced anisotropic diffuse scattering in the tetragonal phase of phase NBT-Ba0.11 lends support to the idea that the massive tetragonal to rhombohedral phase transition in NBT at around 503-573 K, which is absent in NBT-Ba0.11, may be the key to understanding the local structure found repeatedly at room temperature in this complex material.

Original languageEnglish
Pages (from-to)311-317
Number of pages7
JournalSolid State Sciences
Volume12
Issue number3
DOIs
StatePublished - Mar 2010
Externally publishedYes

Funding

FundersFunder number
European Network of Excellence FAME
Secretaría de Educación Pública
Engineering and Physical Sciences Research Council
Consejo Nacional de Ciencia y Tecnología

    Keywords

    • Crystal structure
    • Ferroelectrics
    • Lead-free piezoelectrics
    • X-ray diffuse scattering

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