Origin of large recoverable strain in 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO3 near the ferroelectric-relaxor transition

Piezoceramics of composition 0.94(Bi0.5Na0.5)TiO3-0.06BaTiO(3) demonstrate large recoverable strain at elevated temperature (T > 75 degrees C), which is absent at room temperature. In situ neutron diffraction was used to measure changes in the crystallographic and domain structures during electric field application at temperatures ranging from 25 degrees C to 100 degrees C. Quantitative evaluation of the ferroelastic domain volume fraction in the field-induced phases enabled calculation of the strain contribution from non-180 degrees domain switching. The large recoverable strain is shown to be associated with the reversible nature of the phase transformation. These findings have implications to additional BNT-xBT-based composition and other relaxor ferroelectrics. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790285]