Visualization of Bi3+ off-centering in the average cubic structure of (Ba0.70Bi0.30)(Ti0.70Fe0.30)O3 at the electron density level

We present here evidence for the off-centering of Bi3+ symmetrically distributed along the six < 100 > directions of a pseudocubic composition (Ba0.70Bi0.30)(Ti0.70Fe0.30)O-3 at the electron density distribution level. We also calculate the strength of covalent bonding between the oxygen (O2-) anions with A-site (Ba2+/Bi2+) and B-site (Ti4+/Fe3+ ) cations, which provides evidence for the stabilization of average cubic symmetry. We believe that Bi3+ positional disorder may be ubiquitous in all the lead free piezoceramic solid solutions of the type (Ba1-xBix)(Ti1-xMex)O-3, where Me Fe3+ , Sc3+ , Al3+ , (Mg1/2Ti1/2)(3+) , and (Zn1/2Ti1/2)(3+) . (C) 2013 AIP Publishing LLC.