Comparing the electromechanical properties of CaTiO3‐ and BaZrO3‐modified Bi0.5Na0.5TiO3–SrTiO3 ceramics

The effects of CaTiO3 (CT) and BaZrO3 (BZ) modification upon the crystal structure and electromechanical properties of lead‐free Bi0.5Na0.5TiO3–SrTiO3 piezoelectric ceramics were compared within a doping range of 0–4 mol%. The different effects of CT and BZ modification upon the phase transition are clearly observed in the polarization and strain hysteresis loops. The CT‐modified specimens maintain strong ferroelectricity without any abnormal enhancement in the electric field‐induced strain. However, the addition of as little as 1 mol% BZ induces a transition from a nonergodic relaxor phase to an ergodic relaxor phase, thus resulting in disruption of the ferroelectric order and the generation of a high field‐induced strain. The present authors believe that the substitution of large ions (such as Zr4+) into the B‐sites, rather than the A‐sites, of the Bi0.5Na0.5TiO3‐based ceramics plays a significant role in the phase transition behavior.