Structure versus relaxor properties in Aurivillius type compounds

• Published in: Journal of the European Ceramic Society Vol. 27; no. 13; pp. 3687 - 3690
• Main Authors: Tellier, J., Boullay, Ph, Ben Jennet, D., Mercurio, D.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 2007; Elsevier
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Electrotechnical and electronic ceramics; Exact sciences and technology; Ferroelectric properties; Perovskite; Powders solid state reaction; Technical ceramics; X-ray methods; Perovskite; Powders solid state reaction; Ferroelectric properties; X-ray methods; Perovskite type compound; Electrical properties; Oxides; Titanates; SAED; Experimental study; Oxide ceramics; Powder; Solid state reaction; Property structure relationship; Electroceramics; Crystalline structure
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2007.02.016

Structure refinements in M IIBi 4Ti 4O 15 (M II = Ca, Ba), Bi 4− x Ba x Ti 3− x Nb x O 12, (Na 0.5Bi 0.5) 1− x Ba x Bi 4Ti 4O 15 and Bi 4Ti 3O 12–PbTiO 3 systems are used to report structural features of relaxor Aurivillius phases. In compounds with relaxor-like behaviour, the average structure is almost undistorted, closed to the archetypal HT paraelectric phase, with a tolerance factor ≳0.996. The coordination number of Bi 3+ in fluorite layers changes from {4 + 2} for ferroelectrics to {4} for relaxors. Transmission Electron Microscopy reveals some characteristic features of relaxors such as micro-twinning, shearing-type defects which attest from the existence of a compositional inhomogeneity and a disorder at a local scale.