Synthesis, structural evolution, and dielectric properties of a new perovskite solid solution (Pb _0.5 Sr _0.5 )(Zr _0.5 Ti _0.5 )O ₃ –PbTiO ₃

To explore lead‐reduced dielectric materials in the SrTiO 3 –PbTiO 3 –PbZrO 3 ternary system, a novel solid solution between relaxor ferroelectric (Pb 0.5 Sr 0.5 )(Zr 0.5 Ti 0.5 )O 3 and ferroelectric PbTiO 3 , namely (1 − x )(Pb 0.5 Sr 0.5 ) (Zr 0.5 Ti 0.5 )O 3 – x PbTiO 3 (lead–strontium–zirconate–titanate [PSZT]–PT), has been synthesized in the perovskite structure by high‐temperature solid‐state reaction method in the form of ceramics. The crystal structure and phase symmetry of the materials synthesized were analyzed and resolved based on X‐ray powder diffraction (XRD) data through both the Pawley and Rietveld refinements. The results of the structural refinements indicate that at low PT‐concentration end of the solid solution system, for example, x = 0.05, the PSZT–PT solid solution exhibits a cubic structural symmetry (with the space group Pm ‐3 m ). As the PT concentration ( x ) increases, the structure of (1 − x )PSZT– x PT gradually transforms from the cubic to a tetragonal ( P 4 mm ) phase. In the composition range of x = 0.10–0.25, a mixture of the cubic and tetragonal phases was identified. As the concentration of PT increases, the proportion of the tetragonal phase increases at the expense of the cubic phase. For a composition of x > 0.25, a pure tetragonal phase is observed. The dielectric properties of the materials were studied by measuring the permittivity as a function of temperature at various frequencies. For the composition of x = 0.05, the temperature dependence of dielectric constant shows typical relaxor behavior. For x = 0.35, the dielectric peaks indicate a normal ferroelectric phase transition. Overall, a structural transformation from a central‐symmetric, nonpolar cubic phase to a non‐centrosymmetric, polar tetragonal phase is induced by the substitution of PT for PSZT in the pseudo‐binary solid solution of (1 − x )PSZT– x PT, which also reveals an interesting relaxor to ferroelectric crossover phenomenon.