A New Phase Boundary in (Bi1/2Na1/2)TiO3−BaTiO3 Revealed via a Novel Method of Electron Diffraction Analysis. (16th May 2013)

• Record Type: Journal Article
• Authors: Ma, Cheng; Guo, Hanzheng; Tan, Xiaoli
• Is Part Of: Advanced functional materials. Volume 23:Number 42(2013)
• Page Start: 5261
• Page End: 5266
• Publication Date: 2013-05-16
• Subjects: Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201300640
• Languages: English
• ISSNs: 1616-301X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A new phase boundary is revealed in (1–<italic>x</italic>)(Bi_1/2Na_1/2)TiO₃−<italic>x</italic>BaTiO₃, the most extensively studied lead‐free piezoelectric solid solution. This discovery results from a novel method of electron diffraction analysis, which allows the precise determination of oxygen octahedra tilting in multi‐domain perovskite ferroelectrics. The study using this method supports the recently proposed <italic>Cc</italic> symmetry for pure (Bi_1/2Na_1/2)TiO₃, and, more importantly, indicates the crystal structure evolves into the <italic>R3c</italic> symmetry with the addition of BaTiO₃, forming a <italic>Cc</italic>/<italic>R3c</italic> phase boundary at <italic>x</italic> = 3–4%. In the poling field <italic>E</italic>_pol versus composition <italic>x</italic> phase diagram for polycrystalline ceramics, this phase boundary exists with <italic>E</italic>_pol below 5.5 kV mm⁻¹; the <italic>Cc</italic> phase is transformed to the <italic>R3c</italic> phase during poling at higher fields. The results reported here provide the microstructural origin for the previously unexplained strain behavior and clarify the low‐BaTiO₃‐content phase relationship in this popular lead‐free piezoelectric system.</p> </abstract>