Dielectric and piezoelectric characterization of PSZT–BT ceramics for capacitor applications

The ceramic compositions (1 − x)Pb_0.9875Sr_0.0125(Zr_0.53Ti_0.47)O₃ –xBaTiO₃ where x = 0.2, 0.4, 0.6 and 0.8, fabricated through solid state reaction method were investigated for phase formation, microstructure, density, dielectric and piezoelectric properties. The X-ray diffraction patterns indicated that introduction of BaTiO₃ in isovalent donor Sr modified PZT lattice, diminished the tetragonality. All the specimens were homogenous in nature due to the coarse grains of BaTiO₃, which had undergone inter-granular growth and were homogeneously distributed within the PSZT–BT lattice. Introduction of BaTiO₃ in PSZT perovskite lattice resulted in enhanced grain growth till x = 0.6 (2.03 μm). Dielectric properties (ε_RT, Tanδ and T _c) were influenced by both BaTiO₃ and Sr. The maximum ε_RT = 1588 and ε_Tc = 10478 were found in 0.2PSZT–0.8BT ceramic system. The optimum dielectric permittivity at room temperature with a low Curie transition temperature was found in 0.2PSZT–0.8BT composition. Piezoelectric properties are very sensitive to isovalent substitutions, where isovalent donor Sr modification and BT concentrations in PZT, affected the piezoelectric properties (k _p and d ₃₃) in the ceramic system. Thus, the series PSZT–BT compositions could be ideal candidates for capacitors and suitable sensor applications.