Microstructure, dielectric properties, relaxation behavior, and ferroelectric properties of Gd-doped lead-free BZT ceramics by sol–gel process

In this work, Gd₂O₃-doped BZT ceramics were prepared by the sol–gel method. Microstructure, dielectric properties, relaxation behavior, and ferroelectric properties were investigated. The grain size changed significantly with the increase of doping content. When the doping content x = 0.9, the system demonstrated excellent dielectric properties (ε_r = 7788, tan δ = 0.021)., and the dielectric constant remained stable in the high frequency range. As the doping content increased, the relaxation behavior of the system enhanced due to the lattice distortion and the generation of oxygen vacancies. In addition, when x = 0.9, the system had excellent ferroelectricity (P_r = 8.84 μm/cm³, E_c = 2.35 kV/cm), because of the domain inversion and the movement of the domain wall. It is believed that the system with enhanced dielectric properties and piezoelectric properties may be a suitable candidate to replace the lead-based materials.