Structure and ferroelectric properties of Bi(Zn1/2Ti1/2)O3-(Bi1/2K1/2)TiO3 perovskite solid solutions

Lead-free piezoelectric ceramics based on chiBi(Zn_1/2Ti_1/2)O₃-(1-chi)(Bi_1/2K_1/2)TiO₃ were obtained via solid state processing techniques. A single perovskite phase with tetragonal symmetry was obtained for Bi(Zn_1/2Ti_1/2)O₃ (BZT) substitutions up to 20 mol%. The maximum density was 97.1% at the composition of chi = 0.1. The dielectric measurement indicated that the transition temperature decreased linearly with increasing BZT content. The P-E loops revealed an increase in remanent polarization (P_r) with the addition of BZT. The maximum planar coupling coefficient, kappa_r, for the chi = 0.1 composition was 21.6 and the piezoelectric coefficient, d₃₃, for chi = 0, chi = 0.05, and chi = 0.1 was 108, 185, and 235 pm/V, respectively. Overall, the dielectric and piezoelectric properties showed significant improvement when BZT was added.