Relaxor Characteristics of Morphotropic Phase Boundary <scp> (Bi _1/2 Na _1/2 )TiO ₃ –(Bi _1/2 K _1/2 )TiO ₃ </scp> Modified with <scp> Bi(Zn _1/2 Ti _1/2 )O ₃ </scp>

Abstract

Morphotropic phase boundary (Bi 1/2 Na 1/2 )TiO 3 –(Bi 1/2 K 1/2 )TiO 3 ( BNT–BKT ), was modified with increasing additions of Bi(Zn 1/2 Ti 1/2 )O 3 ( BZT ). Microstructure, electric‐field‐induced strain and polarization, dielectric permittivity, and temperature‐dependent piezoelectric coefficient were investigated and compared with crystal structure measured in situ as a function of applied electric field. Furthermore, permittivity and piezoelectric coefficient were characterized as a function of electric field. For small additions of BZT , an applied electric field leads to an irreversible phase transition into a ferroelectric phase with remanent polarization and a reduced relative permittivity. Increasing the content of BZT increased the threshold field for the transition. For additions of more than 2 mol% BZT , the piezoelectric coefficient dropped, permittivity remained almost constant, and a high normalized strain of up to 500 pm/V was observed. However, no field‐dependent structural change was evidenced by the in situ X‐ray experiment.