A generalized rule for phase transition generated by additives in piezoelectric ceramics

The phase transition generated by additives has not been defined systematically in (1-x)Pb(Zr,Ti)O3-xPb(BI2+ 1/ 3Nb2/3)O3 (PZT-PBN, BI2+: Mg2+, Zn2+, and Ni2+, in this study). In order to define the phase transition of PZT-PBN, we identify the various phase transitions depending on the ionic site which an additive enters. The ionic site can be determined by the ionic size of a metal in an additive, and in the ABO3 of a perovskite structure, the phase transition is more significant when an additive enters the B site, compared to the A site. Until now, the phase transitions have mostly been described as the vertical or horizontal transitions in phase diagrams. However, in this study, we show that phase transitions actually occur in the diagonal direction. In particular, it is reported that a unique shift of morphotropic phase boundary (MPB) occurs, when the additive enters the BI2+ site in (1-x) Pb(Zr,Ti)O3-xPb(BI2+ 1/3Nb2/3)O3. The MPB shift is different from the normal phase transitions which are generally observed in PZT-based materials.