Effect of SiO₂ doping on the dielectric, ferroelectric and piezoelectric properties of (Ba_0.7Ca_0.3)(Zr0.2Ti_0.8)O₃ ceramics with different sintering temperatures

In the present study, the doping effect of SiO2 on the dielectric, ferroelectric and piezoelectric properties of the (Ba_0.7Ca_0.3)(Zr_0.2Ti_0.8)O₃ (abbreviated as BZT-50BCT hereafter) ceramics sintered at different temperatures were systematically studied. With the SiO₂ dopant, the distribution of the grain size became more homogeneous. Besides, the average grain sizes firstly increased with increasing the SiO₂ concentrations and then decreased. As the macroscopic properties, the dielectric constant decreased with the addition of SiO₂. The remnant polarization P_r firstly increased and then decreased with increasing the SiO₂ concentration. While the coercive field monotonically decreased with the SiO₂ dopant. And the piezoelectric constant d33 firstly enhanced by the SiO₂ and then reduced as further increasing the SiO₂ concentrations. The maximum d₃₃ of 500 pC/N has been obtained in the 0.5 mol% SiO₂ doped BZT-50BCT ceramics sintered at 1500° from the industry available raw materials.