Electric field effects on piezoelectric and ferroelastic strain in Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 piezoceramics

Rietveld analysis of synchrotron diffraction data is used to resolve the macroscopic strain response of tetragonal barium zirconate titanate-barium calcium titanate (BZT-BCT) piezoceramics and determine the underlying strain mechanisms. A lattice strain contribution and a ferroelastic switching contribution are identified and both contribute significantly to the macroscopic strain. A large electrically induced ferroelastic domain texture is observed that undergoes strong relaxation upon removal of the electric field. This suggests that under cyclic conditions each field application leads to a strong ferroelastic domain reorientation that is identified to be responsible for the good piezoelectric performance observed in this class of materials. Moreover, the significance of orientation dependent structural changes is identified, which is crucial to fully understand the macroscopic strain response.