Dielectric and piezoelectric properties of Fe₂O₃-doped 0.57PSN-0.43PT ceramics

Dielectric and piezoelectric properties of iron-doped 0.57Pb(Sc_1/2Nb_1/2)O₃-0.43PbTiO₃ were investigated. The maximum dielectric constant (ε₃₃/ε₀ = 2551) and the minimum dielectric loss (tanδ = 0.51%) at room temperature were obtained at 0.1 wt% and 0.3 wt% of Fe₂O₃ additions, respectively. The temperature dependence of the dielectric constant was measured between 20°C and 350°C. With the additions of Fe₂O₃, the piezoelectric constant d₃₃ and electromechanical coupling factor k_p were slightly decreased, but the mechanical quality factor Q_m was significantly increased. The highest mechanical quality factor (Q_m=297) was obtained at 0.3 wt% Fe₂O₃, which is 4.4 times larger than that of non-doped 0.57PSN-0.43PT ceramics.